ssh has the -i option to tell it which private key file to use when authenticating:

-i identity_file
     Selects a file from which the identity (private key) for RSA or DSA
     authentication is read.  The default is ~/.ssh/identity for protocol ver-
     sion 1, and ~/.ssh/id_rsa and ~/.ssh/id_dsa for protocol version 2.  Iden-
     tity files may also be specified on a per-host basis in the configuration
     file.  It is possible to have multiple -i options (and multiple identities
     specified in configuration files).

Is there a similar way to tell git which private key file to use when on a system with multiple private keys in the .ssh directory?