Lets see why would I want a psp?

Better graphics
Also has wireless capability
Will probably have a better range of software (more developers will want to get onto the sony bandwagon)
More original games (why dont we all play games we played on the N64 7 years ago... but slower.)
Doesnt rely on cartiges (seriously, why do you think the N64 failed?)

apart from that.

And specs WERE realeased on it (around the time it was announced) but they may have been changed since then.

EDIT: aslo FF7:AC will be realeased on DVD and 70% of PSP games are completly origonal (Including some great looking new RPGs)