Ed2010--Ed 2010 is a website dedicated to young professionals in the publishing industry. They have job and internship listings, as well as mentoring services and advice columns.
MediaBistro--MediaBistro is a community for media professionals. They have job and internship postings.
Conde Nast--Publishers of Vogue, W, WWD, Glamour, etc. Job postings and a summer internship program. Interns must be juniors, seniors, or recent graduates.
Hearst--Publishers of Harper's Bazaar, Cosmopolitan, etc. Job postings and internship program (spring, summer, and fall).
Free Fashion Internships.com--Internships are available design, merchandising, marketing, sales, showrooms, and publishing.
Liz Claiborne--Liz Claiborne's internship program is legendary. There are internships in every field imaginable at labels like Liz Claiborne, Juicy Couture, kate spade, DKNY Jeans and more. Juniors, seniors, and recent graduates only. Job postings are available too.
Kenneth Cole--He of the pithy sayings and eco-friendly shoes offers internships in many departments. (No listings currently, but this will probably change soon. You can also just send your resume in.)
Diane vonFurstenburg--She of the awesome wrap dresses and awesome crystal egg apartment is also looking for internships for the spring. Departments include PR/Marketing, Design, Merchandising, Operations, Retail, and Sales. They're also looking for sales associates.
The Metropolitan Museum of Art--The Met has internships available to juniors, seniors, and recent graduates at both the Costume Institute and the Antonio Ratti Textile Center. Freshmen and sophomores can apply to an education internship at The Cloisters.
The Textile Museum--Located in Washington D.C., this museum is dedicated to non-Western textiles. Internships are available in communications and marketing, conservation, curatorial and collections management, development, and education.
Costume Society of America--Job and internship postings. I secretly want to be a member. Why are you so expensive?!
Cora Ginsburg--Cora Ginsburg is a gallery dedicated to historical textiles and costume. They appraise and sell items to private collectors and museums. It also looks like the best job in the history of the world.
In addition to these sites, there are always general job search engines like Monster, as well as the many general internship search engines offered by the CDO. You can ask your lovely pals at Contrast if they have any ideas, or even your professors or family friends. Sometimes the best thing to do is cold call (or, in this case, cold e-mail) stylists, costume designers, fashion designers, etc. They might not have any listings on their site, but that doesn't mean they won't consider taking an extra person on, especially if you wow them with your wonderful, fabulous resume. Which you all have, because you are wonderful and fabulous people. Good luck!