There are plenty of options for buying unlocked smartphones. I've used this company before and they are pretty reliable.
CeX (UK) Buy & Sell Games, Phones, DVDs, Blu-ray, Electronics, Computing, Vision & CDs
Just click on to the store near you and browse the selection of phones available. I can't comment on Blackberrys but iphones are easy to unlock yourself. There are plenty of tutorials on youtube to do this.