That works, thanks.

I noticed that KNOPPIX use a some what different method by listing all (stable/testing/unstable) sources and use apt.conf to control what default to choose from.

I am wondering if it this case, there is any application which present the information in a nice way such that I can from one single interface to choose which distribution to pick from. Or may be I need to fallback to apt-get(which is a command line utility) pick which distribution to download from.