This is an interesting development. More and more solutions based on Microsofts RDP protocol are being developed to bring applications to the desktop with seamless Terminal Windows (without the full desktop that usually comes with the Microsoft RDP Client). In the past this was typically a domain of Citrix, which is quite expensive.
Open Source Seamless RDP Client with Source Code
AppliDis Seamless Client - Applidis free module
Tarantella Carnaveral IQ - not free but much cheaper than Citrix
WTS Gateway Pro - lowcost ressource-based Terminal Server Load Balancing - works very well!