How to nofollow all the outbound links?

Hey Everyone,

I am building up a directory and I want to make all the outbound links nofollow?

I cannot do it manually, because there are more than 1000 websites. Is there any script to do it?

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

See the post by Siton_Systems (near the bottom) on this topic.