Zavvi currently have a sale on instore and there are a few bargains to be had. They had loads of the PSP/PSP Slim & Lite Essentials packs.
The Essentials pack includes:
Gamexpert PSP Carry Case
4 x UMD Storage Cases
USB Link Cable
Wrist Strap (I think they listed 2 on the back of the box)
They also had loads of copies of Transporter 1 & 2 boxsets for £4.