The big change is that it uses a 3g network which means the internet will be twice as fast as the old internet, so instead of feeling like a wounded turtle on dialup, it will feel like a fully functional turtle on dialup!
There is also supposed to be real GPS built in, and there will be the new iphone 2.0 software. Here is a summary of the keynote:
http://www.mahalodaily.com/2008/06/10/md139-steve-jobs-wwdc-keynote-in-60-seconds/
http://www.fixmymovie.com/splash/ will take you crappy looking movies from a mobile phone or other device that does not take great movies, and processes them and turns them into slightly better movies.
If you want to turn you mac mini or older mac into a media center you can now download the xbox media center for mac. It will play more movies than apple tv, and has a lot more features.
http://lifehacker.com/389217/xbmc-turns-your-mac-into-the-ultimate-media-center
The media center is a bit hard to use, this web page describes using itunes instead, which is much easier to, but won't play as many files.
http://www.hicksdesign.co.uk/journal/mac-mini-media-centre
downloads:
http://www.macupdate.com/info.php/id/27302/xbmc
http://tv.aninga.net/XBMC/?C=M;O=D
Firefox 3 is finally out, the biggest features is that it is much faster than 2 and it uses a lot less memory.
A list of features. My favorite new feature is the instant bookmark button, and a close second is the open tab I accidentally closed...!