Quidco are currently offering £110 cashback on confirmed blackbery contracts and vodafone are doing the first 3 months line rental free
Free blackberry curve 8250 or 8900 or a blackberry bold for about £42.50
Package includes 500 xnet minutes, unlimited landline calls, 250 texts and email and web
24 month contract is the main downside
Over 24 months you pay 21x£25 - 110 quidco = £17.29 per month
I'm not aware of any better deals at the moment, but if there are then let us all know!