Monster Hunter isn’t really popular in North America. Monster Hunter Tri is supposed to change that but we shall see come release. On the other hand in Japan Monster Hunter is incredibly popular, so the fact that its getting a PSP spin off is probably pretty exciting.
The spin off features the cat like characters from the series and will be going to be on the PSP. That is about all we know at this point. In the mean time you can watch the cats dance beside the logo.