Launching a Local Website Creation Service - Best choices, best options?

Hey guys!

I'm launching a website service where I'd like following:

Signup page, with subscription choices.
Translation of all the WPMU, incl. plugins/themes etc.

Do you have any suggestions to which plugins I should choose and what are the best, easiest and fastest way to translate it all?

Is there any better option than Paypal?

Thanks!