Here are some sites that I found helpful as a Borrower at Prosper:
1.) Prosper Discussion Boards (found on the Prosper.com site as a sub-heading under "Help"). Even though there are separate forums for Borrowers and Lenders, make sure you look through both. Not only will you find great tips on how to do your listing, you will learn the general feeling of those lending at Prosper.
2.) Prosperl.icio.us. This is a blog written by a Prosper Lender mostly about lending, but he gives some great information for Borrowers (found by scrolling down on the right sidebar). It also doesn't hurt to read some of the other posts as well even though they are geared towards Lenders.
3.) Eric's Credit Community list of delinquent loans. Why look at that? While most delinquent loans are from High Risk Borrowers, there are still some late payments made from those with good credit. It just shows that anyone can be delinquent and you need to present your case to show you can and will repay the loan.
Even though my listing is already up, I'm still learning more and more. If my loan doesn't happen to fund, I've learned things from these sites that I can do better in regards to my listing if I choose to try it again.
Index of My Borrowing Experience with Prosper