Ui/mockup tools...

hi.

looking to create a couple of rather detailed UI/Mockups... any webbased/desktop tools for the linux environment... the intended apps are to be web based.

apps that produce prototype html that can be walked through would be good. looking for something cheap, and not too complex. also, looking for an app that spits output that can be shared/edited by future (possible) team members..

thanks

bd