Renaming my URLS and its affect on Google rankings?

hey guys,
I recently came upon the ALBUM SELECT module and see that it will be very helpful for my currently Gallery2 layout. The problem was that when I originally built my site in January 2008, I was not aware of the album module and therefore did not plan the structure of my album navigation correctly.

I want to use the ALBUM SELECT module, but that means I will have to rename some of my URLS and I was wondering if this was going to be bad for my Google/Yahoo rankings?