Looks like the biggest update will be support for high-speed EV-DO and a smaller form factor:
If you thought the first Pearl was small, then know that the Pearl 2 will be even smaller, shaving nearly 8mm in depth and 30% of its weight to be competing with RAZRs. Still, the Pearl 2 manages to squeeze in a 2MP camera (upgraded from 1.3) and a MicroSD card.The new Blackberry Pearl 2 will arrive in the fourth quarter of this year.
The first BlackBerry Pearl