If you've not registered to vote yet (tut tut!), you can download the voter registration form here: http://www.birmingham.gov.uk/Media/VOTER%20REGISTRATION%20FORM%20FRONT.pdf?MEDIA_ID=78430&FILENAME=VOTER%20REGISTRATION%20FORM%20FRONT.pdf.
Only thing is, the top of the first page says 'See notes overleaf before completing this form', but the second page is blank. I've contacted the Elections Office about this, so watch this space..!
Update (01/02/2006): As a result of my inquiry, the Elections Office will be republishing the form on their website to include both pages. You can use the existing version if you want, as only the first page is required for registration. Sorted!