Non-Microsoft project management tool

[I am Spartacus]

okay, so the higher-ups have warned me that in an effort to better track 
our projects at the office, they are thinking of implementing Microsoft 
Project and requiring that we manage and update our programming projects 
through this software.  I'm looking for references to 
platform-independent (preferably web-based) project management solutions 
that will provide a full spectrum project management solution.  Most of 
our programmers are much more comfortable in Linux and Unix, and I don't 
want to buy in to an expensive tool that requires the Windows platform 
and a high learning curve.  Anyone know of a product that will do what 
Project does, or at least most of it, but is not tied to the Microsoft 
platform?

Shannon Merritt