For those looking for an easy approach to using "loadby" without needing to know what version of .NET you are working with, you could use a script found here:

http://naveensrinivasan.com/2010/07/26/script-to-load-sos-within-windbg-based-on-net-framework-version/

The script in question is:

!for_each_module .if(($sicmp( "@#ModuleName" , "mscorwks") = 0) ) {.loadby sos mscorwks} .elsif ($sicmp( "@#ModuleName" , "clr") = 0) {.loadby sos clr}

It probably would be best to have this saved to disk and just load it in the debugger, but I simply coppy and past from commonly used list of commands / scripts.