<p>Is there anything that has features of TFS(Like Source Control, Debug, Testing,...) that we can use in a workgroup with a small team(say 1-6 persons)?</p>

<p>BTW: we are using VS 2008 Team Suit</p>

Do you particularly need it all in one package? Various open source projects only do one thing, but integrate nicely with others. For instance:
Subversion
for source control
Trac
for bug tracking
Cruise Control .NET
for continuous builds
NAnt
for build management