You should be able to setup a share on the MacBook Pro and then connect to it with Time Machine. There's a few different articles online on how to do this - one of them is here:
How to Create a Time Machine Backup to a Network Drive in Lion | Basil Salad Software
Thank you. I do not have a Time Capsule. I'm looking to use my MacBook Pro as a Time Capsule for an iMac. Do you know if this is possible? Thanks.