XboxToday is carrying a guide on how to surf the internet on your Xbox 360... I've taken a look at the procedure, and honestly it's not really a "standalone" client, you need to have a PC hooked up to the Xbox360, and really then all it does is just lets you...Well, take a look for yourself. I'm a Mac user, so it's not compatable for me - If somebody could try it out and let me know, I'll update the post

Instructions after the jump

...Owls freakin rock my socks

First thing you must know is that you need Windows XP Media Center edition, no other OS will work with this.
1) Go to http://www.anpark.com/software.aspx
2) Click on "Download Now (591 Kb)"
3) Double click on MCEBrowserSetup.msi and just click next
4) Start your Xbox 360 and go into Media Center
5) Go into "More Programs" and choose the "Browser" Entry.
6) Add Favorites to your 360 from your PC, by going into: C:, then "Documents and Settings" folder, then the "MCX#" folder
The # symbol represents how many times you connected your Xbox 360 to your PC, always choose the highest number.
Go into the Favorites subfolder and then you are able to drag and drop then from Internet Explorer and its address bar.
Finally choose one of the Favorites from your list and bingo, your in! This does not let you type in any web pages or anything, it basically just allows you to view the Internet Explorer from your PC on the 360 screen. Since the IE runs straight off your computer, you will also get no viruses whatsoever.