Is there any way to use Microsoft Streets & Trips on an android device such as Galaxy Tab 2 or Google Nexus?
There are several RDP/VNC application on Android, which can be used to "run" any Windows application.
What you basically need to do is fairly straightforward:
Citrix and Azure virtualization platform can be accessed by regular off-the-shelf RDP viewer. As an alternative, many open source or off-the-shelf virtualization software like VirtualBox or VMWare also supports RDP or VNC protocol for remote displays of their virtual machines.
How to set up the server is outside the scope of [android.se], try [superuser] or [serverfault]. Once the server is setup, it's fairly straightforward to setup the Android part, come back with a more specific question if you had trouble when you get there.