When I entered Turkey in November the fee was indeed $100 (or 100 euro if you prefer) to get a visa placed in my US passport. You do get a little extra for your money though - I got two of the old EUR 45 stickers plus one of the EUR 10 stickers the other nationalities get!

There seems to be a surprising number of supposedly reliable information sources that aren't up to date on this. (When I went on my trip fodors.com still said $20!) The list of Foreign Entry Requirements from the Department of State Web site apparently still lists the old $45 fee - not surprising since that page was updated in May 2002 and that's what the fee was at that time. If you check the latest Consular Information Sheet for Turkey on travel.state.gov, you'll see it reflects the increased visa fee.

Sorry to be a burster of bubbles but just remember, if the Turkish authorities wanted to be really, really fair they'd match the US visa fees as a percentage of per-capita income and you'd be paying more like $500 to enter the country. So consider yourself lucky - it's the people on the other end who really got screwed.