A post on the US PlayStation blog has revealed a new firmware update for the PSP is coming out today.
Update v.3.93 "expands support for PlayStation Network titles", apparently.
In addition, it'll offer users of the PSP Internet Radio feature 20 new players, organised into different musical genres. According to Sony more than 50 per cent of PSP owners use their handheld to listen to music. There's a guide to using the IR feature elsewhere on the PS blog.
PSP firmware can be downloaded from the UK Playstation website.