Curt Zirzow has pointed out a cool article on the Box.net website about debugging your PHP applications with a combination of Vim and XDebug (on linux).

Here's how it works. You're coding away in vim. You hit F5; Vim waits for a connection from the PHP server. You refresh the PHP page you're working on. It attempts to contact Vim - connection successful. You are launched into a debugging session right inside Vim. You can step into, over, and out of statements, eval statements, get all variables in context, get and set properties, remove and set breakpoints, all on the fly. Finally, some real programming tools.

Included are the steps to set up the vim environment , set up the client debugger (DGBp) and link it all to the XDebug functionality on your remote machine.