Lona. found this for you, I hope it helps
ISP Migration: ADSL Broadband Accounts
Description: Transfer your ADSL number from one ISP to a new ISP with minimal loss of service. This can be done by some ISP's with the few minutes it takes you to apply your new user name and password to your connection settings. Please note that not all ISP's are yet able to do this smoothly eg Gio this is an example of one ISP who prefer new users not to use the migration process. Gio prefer you to leave your original ISP and use a dial up connection then order their ADSL BB as a new customer. An example of an ISP who is accomplished with the migration process is Eclipse. There is a migration fee as BT charge ISP's to use this service but it does mean you will not have to revert to 56K.
How To: Start the Process
Contact your ISP to obtain your CBUK number which contains all the details about your ADSL account. This is data protected but allows both ISP's to communicate all the necessary details needed to activate your request.
Contact your new ISP giving them the CBUK number. Eclipse has an online form to fill out which also sets up your new e-mail address and web space. You must choose the same package your are currently using i.e. 50:1 contention rate which most users have. Once your account is set up you can then upgrade to 20:1 or 1MB if offered.
The next stage is between both ISP's. You can check the progress of your order online as this is updated at each stage. There are a lot of loops in this part as details have to be sent to BT Wholesale who then contact your ISP asking them if they permit your line to be released. Your ISP will contact you to confirm this request has been made by yourself. The loop goes back to BT wholesale who then loop to BT communications to obtain a release date. This date is then sent back to your new ISP who will advise you of the actual date you will be transferred.
Your status sheet should then show all the settings you need to know for your mail servers plus allocate your new user name and password. This can all be viewed by logging into your account with your new ISP. Your original ISP should also confirm by letter and replace your account to a dial up. You do not need to use the dial up connection but it is wise to keep it for a while as you will be able to access your e-mail account unitl you are sure everyone knows your new address.
On the due date your ISP will release your ADSL line: this will be obvious as you will realise you are not able to send mail or continue to browse the Internet. As soon as this happens change your user name and password via your modem or router, refresh the page and you will now find you are using the services of your new ISP.
If it doesnt sorry Its Friday night Hic (yes already)