My daughters best friend is 17 and was put into foster care Friday night she wants to come live with us, I would be more than happy to take her but not sure where to start.

I would find out who the case worker is. Also, whether her mother voluntarily placed her or if she was removed by the authorities. If mom placed her, mom may have a say in where she goes.

At 17, I would guess more consideration also will be given to where she wishes to be. You can call your county human service department (the county where the girl resides) and ask them about it - they should be able to provide some guidance.