I filed bankruptcy in 2005. I need a loan - will I be approved if I have a co-signer with good credit?

Depends on the kind of loan you are looking for, the status of the Bankruptcy and the bank. If you are still in the bankruptcy you will need a letter from your trustee stating the terms under which you can purchase something. If the bankruptcy has been discharged and everything is in good standing otherwise you might not need a co-signer. Otherwise it will depend on the type of loan.