Can Linux have spyware?
 

Hey I was just thinking about it ... but is it possible for unix/linux to have spyware??

Anything is possible, but I doubt anyone will waste their time making spyware for Linux when Windows is what 99% of the home users use.

But how? I mean Windows has a regestry
How would spyware install itself on a *nix box and modify start up?
it wouln't have root permissions ... I dont think it is possible to do it

You don't need a registry for spyware.
Spyware could, potentially be installed as an extension to whatever browser you are using. Mozilla/FF explicity asks if you wish to install an extension, so called 'drive by downloads' won't work. Other than that, spyware could be incorporated into an app (lower chance if it's Opensource, but if you want to be sure, check the code)

Other, less melicous stuff, such as bad cookies could be installed, btu that's about it.

There is also a way of dynamically loading modules to the kernel. AFAIK root kits work this way, and as such a module runs in ring 0, it has full access to all system resources and can, therefore, spy everything. Spyware, like such integrated into browser plugins, are of course restricted to the rights of the user who is working with it (as long as they don't make use of security holes in kernel or other software which allows them to gain root rights).