Want to be able to clone your private repositories from Github without having to setup additional keys?
You can by forwarding your local users identity.
Add your identity
First you'll need to configure your client to forward your current identity:
ssh-add -K ~/.ssh/id_rsa
N.B. "-K" is an OSX only options to add the identity to your keychain"
Always forward identities
You don't need to do this step if you want to only forward identities on specific connections, however it's unlikely you'll want to do that. To always forward you can create an alias to ssh to always add the forward key.
alias ssh="ssh -A"