I expect that there will be *plenty* of units available in the stores then.

Looks like they embedded the battery in hope to keep it away from those "pandorized" batteries enabling custom firmwares. This is a bad trend (Apple does that too on their new MacBooks) because batteries don't last forever and it makes the PSP useless when the battery is dead, as it wouldn't be worthwhile to replace it at that time .

While you're checking out iFixit's site, don't miss the awesome "banana teardown" :-)