CARMELLO'S -- 9108 Center St., Manassas, Va. (703) 368-5522. Open: for lunch Monday through Friday 11:30 a.m. to 2:30 p.m.; for dinner Monday through Saturday 5 to 10 p.m. Closed Sunday. AE, MC, V. Reservations suggested. No separate non-smoking section. Prices: lunch appetizers $2.95 to $4.95, entrees $3.95 to $9.95; dinner appetizers $2.95 to $4.95, entrees $5.50 to $13.95. Full dinner with wine, tax and tip about $19 to $32 per person.

First the good news. Carmello's is a tiny treasure, the plain little Italian restaurant of your fantasies: homey, unpretentious, with excellent food and prices that seem about a decade behind the rest of the world.

Now, for most of you, the not-so-good part. It's in Manassas, a town better known for its battlefields than its restaurants. (We're told even the Civil War buffs bring their own lunches.)

But that's starting to change. There has been a serious effort here to renovate and gentrify the town's central core, to transform its image from sleepy to quaint. Although the project is still clearly in its embryonic stage, it could someday make Manassas a real draw for out-of-towners.

In the meantime, there's Carmello's. It opened in February as one of the first occupants of this new Old Town, and it's already something of a local phenomenon. People in the booming Fairfax area nearby, accustomed to looking toward the District for good restaurants, now have one on their southern doorstep. And they know about it: Carmello's plays to a full and varied house on weekends -- families, dressed-up night-outers, shirt-sleeved locals and, even at this early stage, regular customers, greeted by

Mark and Gail Barnett are free-lance restaurant critics. Phyllis C. Richman is on assignment. name at the door. Where there's a need, word travels fast.

Modest as it is, Carmello's has a wonderfully inviting aura. The place radiates good cheer, partly because of the physical environment -- candlelight, cozily close tables, classical music played softly in the background -- and partly because of the staff, competent professionals who seem genuinely accommodating and committed to helping the place succeed. (Notice that the owner-manager patrols the dining room ceaselessly, a good sign when it comes to quality control.)

The menu is mainly familiar Italian, with a few items left out (calamari, for example). But what they play here they play very well, and they improvise nightly with specials that take off on the old Italian standards with intelligence and real flair. For a restaurant open just a short time, the bumps are remarkably few and far between.

Start out with the good, rich minestrone or, when available, the lovely fish soup, a bright mingling of flavors and aromas. (The various creamed vegetable soups are tasty but too thick.) Or have the mussels, in a broth that's garlic heaven. Or share a pasta. The homemade ravioli, big and properly chewy, are outstanding. The Florentine version has a pleasant cream sauce that's neither over-applied nor overdosed with nutmeg.

Even better are the tortellini, light yet toothy, with a tasty veal filling; the crema rosa version is a delight, with a touch of tomato and parmesan cheese to flavor the cream sauce. The manicotti is exemplary, delicate but with real shape and texture, topped with a light, fruity tomato sauce. The lasagna is a nice rendition, too, thankfully free of the heavy mozzarella shroud that so often chokes this dish. Fettuccine alfredo, commonly smothered with an excess of thick sauce in restaurants, breathes free here, and it's lovely.

And the clams in the clams with linguine may be canned, but they're piled on generously and nicely spiked with garlic -- no complaints at $7.50. Amid the delights, a couple of pasta failures: textureless gnocchi that tasted like unadorned boiled potatoes and cannelloni with a hopelessly mushy wrapper.

When it comes to entrees, pay special attention to the nightly specials -- this is where the chef shakes off the standard Italian restaurant routine and really flies.

For example, look for the terrific grouper in papillote (aluminum foil, actually). The thick chunks of firm fish are steamed with clams, shrimp and scallops in a heavenly tomato/olive oil/wine broth that deserves to be eaten with a spoon. Or try the sole imperial, thin strips of fillet cleverly wrapped, crepe-style, around a chunky crab filling that's lightly eggy (if a touch bland) and served with a very good butter/lemon/ wine sauce. The swordfish has been excellent, too, thick and juicy, its butter-lemon sauce splashed with what tastes like a bit of madeira.

There have been a couple of smashing chicken specials, made with remarkably juicy breast strips topped in one version with slices of ripe avocado, in another with fresh asparagus spears. Both are then covered with a thin, almost translucent veil of mozzarella and baked with a bit of tomato/garlic/white wine sauce.

The veal is first rate, and it shows up in some excellent specials -- veal zingara, for example, features a lively, robust sauce with black olives and bits of gherkin. The lusty filet mignon pizzaiola is another solid choice among the specials.

In the list of regular entrees, there is a quartet of winners: excellent scampi gamberi, with fresh-tasting shrimp just coated by a butter/lemon/wine sauce (no puddles on the plate here); two firm, flaky whitefish dishes, one saute'ed in an egg batter, the other with tomatoes; and zesty, fennel-laced Italian sausage, served with green pepper and a winey tomato sauce.

Carmello's wine list, mostly Italian and Californian, is as modestly priced as the food. Remarkably good at $12 is the 1980 Cavit cabernet sauvignon, lighter and less complex than most, but smooth and nicely astringent. Or, at the same price, try Est! Est!! Est!!!, a full-bodied Italian white whose odd name is explained on the back of the bottle -- this is one of the few wine labels that tell a good story.

Desserts, made in house, have been well worth a try, particularly the mocha layer cake and chocolate mousse ladyfinger cake, both light textured but intensely flavored.

A final warning: Be prepared for crowds. To avoid the crush and the possibility of a long wait, make a reservation for early in the evening, preferably on a weekday.

Even when you've discovered a magic goose, there's no point in standing in line for the golden eggs. ::