Editing Signon Screen

Hi there

Bit of a noobie to WP but have managed to alter one or two things so far!

What I would like to do, is CENTRE ALIGN the ‘Register / Lost Your Password?’ links that appear underneath the Signon box.

I’m happy to go down into the code to do it bur wondered if someone could point me to exactly where I need to go.

Thanks in advance!

Regards
Nicky