Looks useful but reading the comments on that page it sounds like it may cause some problems as well.
There is a list of keyboard shortcuts here http://msdn.microsoft.com/en-us/library/da5kh0wa%28VS.80%29.aspx you can use the - key on the number pad to collapse a tree but unfortunately it does not work if you try it at the solution node, it does work if you select a project node it will collapse the folders in the project so it offers no real savings vs clicking the node to collapse it. Maybe VS 2010 has an improvement for this, I haven't tried it yet.
Best,
Joe