Billy Carter offers some comments on his brother's administration in the February issue of Penthouse that may set the Washington new year off to a rollicking start when copies hit the stands next week.

"Jimmy's got too many young kids around him," Billy suggests. "What he's got now is infighting between everybody on the staff. Frankly, I don't trust any of them enough to talk to them. I don't turst them being around Jimmy. I think they're stabbing each other in the back more than they're helping Jimmy."

Billy describes Carter's adviser Charles Kirbo as "the dumbest bastard I ever met in my life," addig, "I think he's too damn dumb to be dishonest." Of Jody Powell, he says he'd be better off "running a farm in Vienna," the small Georgia town Powell grew up in.

And for assistant to the president Hamilton Jordan Billy reserves the observation, "I think Ham's an a... myself... I don't know what the hell Hamilton does."

Although Billy doesn't dispute that he's pulling down about $300,000 a year in personal appearances, he does claim that the only thing his brother's election has provided him with is federal harrassment.

"The wormy little bastards who are with the IRS came over and I gave them three beers," he says. "And they came back and figured that, because they didn't pay for the beer, I owed the IRS $74 for the beer that I gave away and drank myself and didn't pay for. Then we has OSHA in there, too -- the Office of Safety Hazards, whatever the hell it is. They cited me. The only service station in the United States ever cited. They charged me for having the fire extinguisher too high off the floor. It was 3-feet-1-inch up and and the regulation is 3 feet."

A White House spokesman said yesterday that they had not yet seen the magazine and therefore would have no comment. Decadence & Real Estate

A beginning and an end: New Times fades into the history of magazine publishing with its sprightly, final issue on decadence while Real Estate Washington, a slick, classy bimonthly begins publishing here with a first issue that breaks even -- an unusual feat in the mag biz.

Oddly enough, the final appearance of New Times is one of its best, pinpointing the ever-growing, apathetic mood of decadence that helped cripple a journal born of '60s political sensibilities. Writing about disco, Andrew Kopkind observes that the music and culture is "an inevitable revolt against the natural '60s" and "affirms the unreal '70s, emphasizing surfaces over substances, mood over meaning, body over mind, going out over staying in." On a somewhat lighter note, titled "A Side Order of Desire," Gael Greene compares food and sex, insults a waiter at the Palace by asking for some mousse for her Lhasa apso, and admits, "I've always wondered what it would be like to eat a baby... "

Full circle from the instantly consumable world of food lies the everlasting world of real estate and Real Estate Washington. With 33 pages of ads and 67 editorial pages it may appeal to more than just the 25,000 realtors who received the first issue free. Nestled between more ads offering financing than might be imagined in these inflationary times are some surprisingly solid articles on foreign investors buying up huge chunks of the surrounding countryside, businesses in search of corporate offices here and the conversion of old buildings in the District into condos. All of this is gussled up with some of the classiest graphics we've seen in any local publication.

"Our audience," says editor Randy Rieland, "is anyone in the real estate business, although we're trying to make this more interesting than most real estate publications." Six issues cost $25 from 8401 Connecticut Ave., Chevy Chase 20015. Antiwar Bombing

Although the FBI knew in 1970 of the planned bombing of an Army research center in madison, Wis., the agency allowed the bombing to take place and then used the event as an excuse for an all-out campaign ag ainst domestic antiwar protestors, the February /March Mother Jones reports.

The bombing of the army center resulted in the only death caused directly by the antiwar movement -- a death cited by both escalate tactics against protestors that included illegal domestic CIA investigations of American citizens living at home.

According to the story, the culmination of none months of reporting, the FBI knew in advance of the planned bombing, had enough evidence to arrest suspected members of the bombing group before the event, and even had police agents -- who already knew what was being carried and what was planned -- follow the van carrying the bombs and witness the demolition. Human Fermentation

If you'll pardon us, we'll refer the reader quietly to the January Human Nature and a fascinating glimpse at the history, metabolism and potential medical problems of flatulence.

You'll be happy to know that the production of flatus -- and a normal person creates about 1,000 milligrams each day -- is caused by the same process used to make champagne bubbly: fermentation.

Now for the serious business brought on by "the polite habits of restraint," Namely diveticulitis, a painful bowel infection common in North America, which some hypothesize is caused largely by deliberately retaining flatus:

"Diverticular disease is a disease of civilization," observes physician Geoffrey Wynne-Jones. "It comes with personal cleanliness, with the motor car and the motor coach. It afflicts the cultured, the refined, the considerate, the people with strong social attachments. It should be recognized as originating in the supression of a normal bodily function." Ins and Outs

Another year of magazines -- there are 4,000 in this country alone -- has come to a close, along with the closing of Viva, New Times, More and My Place. Although this is usually a time to reflect on Esquire's Dubious Achievement Awards, we found them a bit too dubious this year -- particularly after hearing reports that Esquire's fortnightly status has itself become dubious and may revert to the monthlly format. We were amused by an ad for Subaru (that's a Japanese car) in the dubious achievement issue, with Susan Ford standing in front of the item in question which is parked in fron of the Capitol Building. "Take It From a Ford, Drive Subaru," this dubious gem advises. Is there no pride in politics? We're recommending Money's Winners & Losers of the Year in the January issue, with tidbits like the increase of sales in roller skates and the decline of skateboards, food processor sales up 225 percent over 1977, and the London Antiques dealer who sold a pair of Queen Victoria's bloomers for $3,000 three months after buying them for $275.