Ivan, thank you for your quick answer.
I was wondering: does the Sitefinity website need to be rebuilt everytime the module is rebuilt? The module's dll is changed so therefore the sitefinity needs to be rebuilt. Correct me if i'm wrong please :)
Teamcity is a tool that allows us to automate builds based on changes in our subversion repository.
We will try to set it up as a common repository for both the sitefinity site and the modules we're developing.
Regards, Ales Tepina