For a Custom-Tailored Trip, Whatever Your Niche

* The comprehensive Web site StudyAbroad.com ( http://www.studyabroad.com) offers info on educational opportunities worldwide.

Vegetarian/Dietary

* The Baltimore-based nonprofit Vegetarian Resource Group (410-366-8343, http://www.vrg.org) hosts a search-by-location database of vegetarian-friendly eateries.

* Message boards http://veganforum.com and http://www.veganfreaks.net/forum/index.php let vegan travelers compare notes.

* Maryland-based Green Earth Travel (888-246-8343, http://www.vegtravel.com) offers info for those with vegetarian, kosher, halal or medical diets.

* The Travel page on the Happy Cow's Vegetarian Guide ( http://www.happycow.com) includes a guide to vegetarian B&Bs, picks of the world's top veg-friendly cities and information on health stores and restaurants in more than 100 countries.

* The International Vegetarian Union ( http://www.ivu.org) offers a multilingual database for the traveling vegetarian who wants to patronize like-minded businesses and organizations.

* The VegDining.com ( http://www.vegdining.com) restaurant directory is free, though the $4.95-per-year subscription gives access to full listings, recipes and other info. The fee is waived for those with the $14.95 VegDining Card (discounts at VegDining.com member restaurants).

* Run by an executive of the British-based Vegan Society ( http://www.vegansociety.com), the Vegetarian Guides site ( http://www.vegetarianguides.co.uk/index.shtml) posts vegetarian and vegan events and festivals worldwide and markets the destination-focused Vegetarian Guide titles.

* For those who keep kosher, Shamash: The Jewish Network ( http://www.shamash.org/kosher) offers a database of 2,500-plus kosher restaurants worldwide.

* For halal travelers, the Web site Zabihah ( http://www.zabihah.com) features thousands of reviews of restaurants and markets worldwide, searchable by country, state and city.

Volunteer

* The nonprofit Action Without Borders (212-843-3973, http://www.idealist.org) is a great place to start. Volunteers can search the database of more than 72,000 member organizations worldwide by location, area of focus and dates. The travel-specific page ( http://www.idealist.org/volunteer/travel.html) lists organizations seeking volunteers.

* The American Hiking Society (301-565-6704, http://www.americanhiking.org) offers field trips for rebuilding trails and fences on public land in about 30 states. Trips cost about $275. The AHS is also working with the Patagonian Foundation on volunteer trips to Chilean Patagonia.

* Global Volunteers (800-487-1074, http://www.globalvolunteers.org) is a nonprofit international development organization that places about 150 teams each year in one- to three-week projects. The educational, social or medical projects (chosen by the local community) start at $795 per volunteer. In addition to about 20 overseas programs, there are also sites in three states.

* Habitat for Humanity's Global Village (800-422-4828, http://www.habitat.org/gv) offers seven- to 16-day home-building placements in the States, Canada and overseas; cost runs between $900 and $2,200, plus airfare. Habitat can provide fundraising resources, such as a Web site to accept donations.

* Health Volunteers Overseas (202-296-0928, http://www.hvousa.org) runs more than 70 clinical education programs in 25 developing countries and places medical professionals in one-month teaching and training programs. Volunteers cover their transportation to and from the work site.

* The International Volunteer Programs Association (914-380-8322, http://www.volunteerinternational.org) site lists volunteer organizations and includes fundraising and scholarship information.

* Volunteer Match (415-241-6868, http://www.volunteermatch.org) pairs volunteers with the U.S.-based organizations seeking them. If you know what city you want to travel to, type it and your interests into the advanced search form and see if any opportunities pop up.