mobiles.co.uk have the sony xperia X1 on a very good deal:
Contract Cost £35.00 P/M for 18 Months
- 600 Minutes
- Unlimited Texts (Bolt-on)
The Bolt-on can be changed to unlimited data (or internet access) which will result in 100 texts on contract.
£40 cashback on Quidco too
- Jabra BT135 Headset with every contract handset Code: AFBTH.
- Jabra 2010 Drivers Park: HOTUK
They are able to port your number over.
With a similar package:
Vodaphone & CPW - handset £150 +/-
O2 Handset £99