What is Microsoft Transaction Server ?

Answer 1

MTS is a database connectivity tool provided by Microsoft.

Answer 2

A predecessor of COM+.

It is a set of Windows services and objects that allow you to not just manage and commit/roll back database transactions, but actually commit/roll back the actions of COM objects.

It is particularly useful if you have a COM object that performs actions on different databases. You can commit/rollback all at once.

http://www.microsoft.com/technet/archive/transsrv/manage.mspx?mfr=true

http://www.microsoft.com/com/default.mspx