Q:

Traffic shaping (like cFosSpeed)? 

Under Windows one of my favorite software packages was cFosSpeed, a traffic shaping tool.  It yields major performance improvements when, for example, having a video conversation while downloading a torrent in the background. 
Is there an alternative for this under Ubuntu? 

A:

The Linux kernel itself has these capabilities, but for sure, it's not trivial to set up for people not familiar with these in-deep stuffs (using the command line oriented "tc" command which can manipulate the traffic control capabilities of the Linux kernel).  I am not sure that you asks about an easy-to-use GUI, or you need only the theory.  Maybe this helps:
http://lartc.org/wondershaper/
It has at least a script, so you don't need to reinvent the wheel too much :)

