Fantastic phone, regularly available for £90 all in on Orange PAYG (see HUKD (http://www.hotukdeals.com/search?action=search&keywords=san+francisco)). Fantastic that is, with one caveat .. fantastic once its unleashed from the terrible bloatware installed on it by Orange.
It comes with Android 2.1 but runs much better with 2.2. I've paired it with a GiffGaff (http://www.giffgaff.com) sim for some unbeatable unlimited internet android 2.2 phone action (£90 up front, £10 per month).
Free Unlocking Here (http://arrtoo.x10.mx/unlockBlade.php) - IMEI number is under the battery or type *#06# into the dialer without pressing call.
Android update guide here (http://orangesanfrancisco.co.uk/android/how-to-install-custom-roms-android-2-2-from-scratch-on-the-orange-san-francisco-zte-blade). - Its the one i used and managed successfully even after more than a bottle of wine. Great guide.
Clockwork Recovery is ace :D