Google, Twitter and Facebook connect to existing user

[Bartek Philly]

Hello,

I would like to be able to connect to an existing user via twitter, google and facebook account. Right now I am only able to connect via Facebook. How can I now, when a user account is created connect it with twitter and google? I would like this also to be able to be done by users too. My website: http://www.sedziapilkarski.pl

thank you