Williamsburg, N.Y. is a small town just east of New York City full of late 20- to 30-somethings who are about to feel the pride of homeownership. Until recently, this town had little available real estate, but now more than 130 buildings are planned in Williamsburg and Greenpoint, a neighboring area to the north, and that's just the beginning. Pending a rezoning proposal, 75 blocks along the East River will be transformed from industrial to residential use. The plan is expected to be approved in May. Elan Padeh, president and chief executive of the Developers Group, a consulting and marketing firm with 30 projects currently planned in the area, recently told The New York Times that in the next two years 3,000 to 4,000 new units will pop up in Willamsburg and Greenpoint. In the next four to five years, Padeh says it could reach 10,000 to 12,000.