Will Verizon be the only carrier availabe?

Most of the verizon phones cricket customers have been flashing. I dont know to much about that so your best off asking a cricket customer service agent.

Right now, the phone that we are calling the Droid will only be available for VZW, but there is another model that still had a bit of the codename "Sholes" that got passed by the FCC at the same time that is a GSM phone, but not using the frequencies that AT&T and T-Mobile use, so the speculation is that this 'other' model is for European release.

As for being able to 'flash' it for Cricket use, the security of the chip itself looks to be pretty formidiable so flashing this phone with another carrier's firmware might be a ways off. I would guess that if one could 'root' the phone (again going to be hard to do) and then be able to input Cricket's data info, there might be a chance, but I wouldn't hold your breath.