(updated March 2008) I was using Macports to install GNUCash on my Macbook and hit a small road block which may be useful to share: Halfway through install of glib2 my connection dropped out and the install barphed. Every time I restarted it it complained about the checksum being invalid for that package. After a lot of messing around the following two commands seemed to do the trick
sudo port clean --all glib2