I want to cross post this as there have been a number of requests for this sort of thing. But I won't!

A few people have posted 'What is this font' threads in the past year or so.

Well, I just came across this: http://www.myfonts.com/WhatTheFont/

I haven't tried it but I hear that it works quite well.

Ever wanted to find a font just like the one used by certain publications, corporations, or ad campaigns? Well now you can, using our WhatTheFont font recognition system. Upload a scanned image of the font and instantly find the closest matches in our database. If WhatTheFont can't figure it out, you can submit your image to the WhatTheFont Forum where cloak-draped font enthusiasts around the world will help you out!
Enjoy!