The is a payment module for the Realex realauth payment.
http://www.realexpayments.com/

You'll need your own merchant account and shared secret.

It's based heavily on the 2checkout module.

It's working nicely, so I thought I'd put it out there for anybody who might be interested.

Now the warnings!
Use at your own risk, no liability accepted.

My current plan is to
1. Tidy up the code.
2. Improve the code to meet coding standards.
3. Work out how CVS works and commit to Drupal.org

Any help appreciated.

Regards
Alan
Updated 21st October with updated code.
Updated Feb 2nd 2009.