Restoring iphone

[macabre]

I wanted to use my black rained and snowed iphone 3g with o2. I presumed that i could just put the o2 sim in and it would work with no problems but all im getting is no service. Does a snowed iphone work with o2 sims?

Can i restore the iphone through itunes at the moment and still keep my phone at an unlockable firmware, as in 3.2 05.11.07, or have apple released a new firmware?

And if i do restore will that get rid of blacksnow allowing my to use the o2 sim again?

[DeL1873]

have you unlocked it using blacksnow ?