Forget about using the PSP to browse the web - it's a pure gimmick and pretty unusable unless you're in a real jam and have absolutely no alternative (and that includes newspapers!) It really is awful surfing without a touchscreen - using the analog stick to navigate between links quickly becomes annoying after, oh I dunno, the first link.

The Mylo screen is too small, too low resolution to be usable for pretty much anything.

If you want a games machine, by a PSP and don't be disappointed by all the non-game related gimmickery - even as an audio player the PSP is ridiculous, it has to be the biggest and heaviest "portable" MP3 player in the world!

If you're only interested in Instant Messenger functionality, I guess the Mylo with it's keyboard is the best bet, although the small screen will make web surfing a miserable experience.

If you want a device to surf the web go with the Nokia Internet Tablet (the clue is in the name). Enhance the Nokia 770 with a ton of free applications, several of which will cater for the "essay taking" requirement (from basic text editors to full-blown word processors), and it also comes as standard with Google Chat & Google Talk. An application called "gaim" is also available with support for MSN, AOL, IRC, Google and several other IM clients I've never even heard of!