Hey!

I have 3 different instances of drupal running for different projects of the same company on the server. Is it possible to have it configured in such a manner that if a person has signed up for example on drupal instance of project A can directly login to the drupal instance of Project B without having to signup again. All the three instances of drupal are on the same server and they belong to the same company if that helps.

Thx,
Nishit

Comments

Check out the

Check out the http://drupal.org/project/domain and http://drupal.org/project/singlesignon modules.
See also Share a single database across multiple sites but note that it is in need of updating.

To get already used separate database tables unified you might need some sql "trickery".
Test in a test environment first!

PS. You could also just enable openid(core module) and let everyone use that, and if needed have them run their own company open id server.