Galaxy Main Tool Shed
Sits at http://toolshed.g2.bx.psu.edu/, is supported by the Galaxy Team, and is the main Tool Shed of choice.
Galaxy Test ToolShed
Test Tool Shed is made for breaking. If you have some tools you want to try out first before making them public in the Main Tool Shed this is the place to go. Test Tool Shed is at http://testtoolshed.g2.bx.psu.edu/.