not new to the market, but bundling it with a pair of covers is. Meet the PSP Extended Life Battery Kit: a battery, two plastic covers, and a lot of packaging. What the kit does provide for PSP-2000 owners (besides an awkward bulge) is about 80% more battery life -- just 20% for those using the original PSP, and no bulge. Unfortunately, Sony couldn't find room for a 'Ceramic White' cover, so those affected will have to settle for the junkyard van look.
A price has yet to be listed, but expect the battery kit to retail in the $40 range.