Overview:
XLink Kai: Evolution VII lets you connect with other console users around the world, and play online games for free. XLink tricks your console into thinking that the other users it is connecting to over the Internet, are actually part of a LAN (Local Area Network). This is the basis of system-link gaming, where friends would gather around in the same house and play over 2 or more consoles. With XLink, you now have the ability to play with other players all around the world just like XBOX Live!
Features:
- Supports XBox, Playstation2, Gamecube and PSP system-link / LAN enabled games.
- 2 gaming modes (Messenger and Arena).
- Integrated chat in all areas.
- No port-forwarding required on almost all network setups.
- Extremely simple and global user-interface.
- Auto-update on startup.
- Multi-console compatible.
- Compatible with wireless networks (not all wireless network setups).
- Superior compression algorithms for less lag.
- Support for university dorms and proxies such as Italian FastWeb ISP.
- Trusted clan and tournament / ladder arenas.
- Lots more features for you to discover!
- It's free!
Download:
Start here and head over the their website and click on
DOWNLOADS at the top of the page.
If you have read this whole and you are still confused...Ask Questions here and we will be gladly to assist you as best as we can 
Courtesy of XLink Kai: Evolution VII, but I also edited a little bit