Yeah, I'm using the VS 11 beta already :) I remembered hearing that VS11 would build in parallel, but couldn't find any options relating to parallel C# builds in VS (although I could find the C++ ones). This info is still useful though when building from script files, which is often how I first build our codebase each morning after getting latest :)

Muralidharan, if you want to build multiple solutions you would just specify another MSBuild command:
MSBuild /maxcpucount:%NumberOfProcessesToUseForBuild% /p:BuildInParallel=%BuildInParallel% "C:\dev\Solution1.sln"
MSBuild /maxcpucount:%NumberOfProcessesToUseForBuild% /p:BuildInParallel=%BuildInParallel% "C:\dev\Solution2.sln"

If your solutions do not have any dependencies on each other, then you can build them simultaneously. In a batch file you can trigger this using the START comand, so you would have:
MSBuild /maxcpucount:%NumberOfProcessesToUseForBuild% /p:BuildInParallel=%BuildInParallel% "C:\dev\Solution1.sln"
START "MSBuild /maxcpucount:%NumberOfProcessesToUseForBuild% /p:BuildInParallel=%BuildInParallel% "C:\dev\Solution2.sln""

This will build Solution1.sln in the current batch window, and then open another batch window to build Solution2.sln in. Hope that helps :)