MSN Messenger

From PSPWiki

In order to chat through MSN Messenger on your PSP, point the Wipeout Pure browser to http://mob.e-messenger.net/mobile. This will take you to a simple MSN Messenger client (probably originally designed for mobile phones, but it works well with your PSP too).

As of the 1.50 US Firmware, the text input method for form controls does not include all special characters. The one likely to affect many MSN users is the lack of an underscore. If your MSN username utilizes an underscore you will need to either press the right arrow virtual key or press the R trigger