Question: What's the easiest way to checkout a file from our TFS with MSBUILD. 

From what I can see it's to shell out to TF.EXE and manually call the checkout command. Is there really no built in command?!

Answer: 
There really is no built in command. Even worse, the tf checkout command only accepts a single filespec. 

The recently released [MSBuildExtensionPack](http://www.codeplex.com/MSBuildExtensionPack) has some msbuild commands for TFS, but no perf gain there. Under the hood, they shell out to tf.exe
the 'itemspec' can be a list of space-delimited items and can use wildcards.