Great "how to" posting from the blog No Revolution on building an effective presence on MySpace using the band Vaeda as a positive example:
…keeping it simple. Don’t go font crazy. Make sure that you can read the thing. This is made way easier if you use one of the Myspace editing programs…
These guys keep their tour dates current and seem to update their blog on a regular basis.
The final point is that randomly adding a bunch of friends is really a bad idea. Making the most of your current online friends and have THEM evangelize your band, and giving them the tools to work with under their own power, is really key…