According to the BBC, the Identity and Passport Service is set to unveil the first ID cards. These will be issued to non-EU students and marriage visa holders, and are in fact issued under the UK Borders Act rather than the Identity Cards Act.
Of course the cards themselves are a red herring that will please the popular press – they have little practical purpose in verifying entitlement to remain in the UK – because the real issue here is the capture of biometric details in a register for the broader range of purposes covered in the ID Act. Furthermore, the system is (as I understand it) intended to be temporary, being replaced by the National Identity Register if and when that appears. What we actually have here is a proof of concept scheme, so it will be interesting to see how the scheme – and its compulsory participants – fare over the coming months.