Though rumors point to the Pre landing on Verizon next year, it's not stopping users from attempting to do it themselves.  PreCentral forum member Cleanser was able to get the device to make calls and send/receive text messages, however data is still a problem:

"Only problem is that I can't get data to work. Apparently webOS is
checking to see if the device is provisioned or not before allowing a
data session to take place. So my next step would be to somehow bypass
this provisioning check."

According to Cleanser, the hardest part was getting Verizon to accept the MEID onto their network (despite the "open network" claims), but after all of that hard work, hearing the Verizon activation girl is a telltale sign of a job well done.

Source: PreCentral