Here's how Matthew Kennedy describes his Lispy project:

Lispy is a library manager for Common Lisp, written in Common Lisp. All of its dependencies except for GPG (with which signed maps and releases are verified) are written in portable Common Lisp. With this approach you should only need a Lisp implementation installed to get started. The Lispy project has two goals: Implement an easy to use, portable library manager. Provide a wealth of ready to install libraries.

He just released version 0.5 yesterday, so if his goals sound good to you, go give Lispy a try.

Last year Jochen Schmidt wrote his impressions of Lispy, so check that out too.