I used photoshop elements for my current one but picnik is a great free site with editing and collage options and you don't have to download it on to your computer.
picnik.com is very easy! The top says collage, you upload & drag them over & done..then you just save & upload it to tinypic or photobucket to get the url.
Re: how do you make a cute siggy with 2-3 pics?