We have PMS. PSP Message Service that is. A new version is now available from homebrew developer pront0. If you missed the initial release, PMS is an application that will allow your PSP to send messages via ad-hoc. Not, it's not a cranky program.

This new version has improved compatibility with both the PSP Phat and Slim, and a new 3D Wave animation. Here's is the changelog for this release of PMS. The Google translation's a bit gritty from the original German, but hopefully you get the general idea:

* completely new gecodet
* 3d animated (gecodete) Wave / Gu Lua 3d
* Skin browsers / file format. PMS
* 5 Skins voristalliert
* Ergänzbar skins / Add / Delete
* Ad_hoc initialisierung elsewhere agency / verkürtzt loading times
* For the first time with Pront0 boot menu (BETA) / R press start bim mode added
* New options:
* New PMS
* Inbox
* Outgoing
* Skins
* Games / not there yet
* Credites
* Exit
* new logo / design
* u.v.m.

The readme is also in German, but you might still want to pore over it using a translator to know more about the program.