According to the PlayStation.blog, the 4GB Memory Entertainment Pack has been canceled before release. "SCEA has seen significant interest in the Ratchet & Clank Size Matters PSP Entertainment Pack in North America, which includes the updated PSP-3000. As a result, we will be streamlining our PSP hardware lineup and will no longer be offering the previously announced 4GB Memory PSP Entertainment Pack."
Sounds like a bad PR spin to us, but we'll manage. The Ratchet bundle looks like a good deal -- and as the post notes, a 4GB Memory Stick can be found on the cheap at many retailers.