Good client/project management software?

Hello guys and gals. I am looking for a good client/project management software preferably written in php/mysql. What are you designers out there using?

I have been using the same one for a couple years that I wrote myself. But I need more options and paypal integration. I simply do not have the time to rewrite mine due to client work so I am looking for a new option.

I appreciate any links and suggestions.

Thanks

which is best among these?
can i go ahead with ProjectPier?? or do you suggest any best alternative ?

We have a PHP/MySQL system out called NetBill which sounds like it would be a nice fit for you.

I also recommend the products at IHostDev.com which are great if you are also integrating hosting billing.

Also can check Sugar CRM , its very popular