I am in with a bit of the knowledge to freelancing one of my fellow webmasters runs this site, which is dedicated to freelance issues:
Freelancer Panel - Software for all types of freelancers - [Home]
Includes:
Excellent Client-side & Admin-side Design
Full Client Management
Invoices
Full Project Management
Portfolio
Products / Custom Services
Pre-set Pages
I use it myself, and heres what the inside looks like, (alot nicer than the outside!! )
http://www.freelancerpanel.com/images/ss_1_large.jpg
Alex.