Can android phones by locked to a network?

[ghinfo]

Hi. I'm wondering if it is possible for network providers to restrict android phones to just their network? I'm hoping that they cannot because the phones are built on an open source OS (and thus shouldn't be able to restrict functionality) but from reading around it seems to be possible.

I'm asking as I'm intending to get a new android phone but don't want it to be locked to a network provider - this would affect which provider I go with (Vodafone UK don't seem to block but I thought Orange UK did, at least on older generation phones.)

Thanks in advance. Gil

[rje]

All Android phones sold by carriers, except the Nexus One, are locked to the respective carriers.