What websites, publications or real estate professionals would you recommend to people looking for rentals in Chelsea, New York City?

Craigslist is the best resource for finding an apartment in New York. Try "no fee" or "by owner" apartments first under the Chelsea heading. It's hard to go around a broker but that will show you what's out there. If you are ok with paying the fee (most people have to and it's 10% of a year's rent), then do the "all apartments" heading or go directly to the firms' websites. Citihabitats and Bond are two of the biggest and they have pretty comprehensive lists for every neighborhood.