you are in luck. I just did this for our whole enterprise. There are several tools out there that allow you to pipe the password into the RUNAS command, but then there are also tools that emulate runas so it's a bit more secure. No password visable in code or on screen. The one I'm using is called CPAU and can be found at www.joeware.net
I wrote up a perl program that does all the gui stuff for the user.
Once you get the program (CPAU) you do the following.
figure out the command you need to pass from the command line, i.e. runas /user:domain\user "c:\program files\internet explorer\iexplore.exe"
given the above, you would type out the following for CPAU;
cpau.exe -u domanin\user -p password -ex "c:\program files\internet explorer\iexplore.exe" -enc -file C:\IE.job
This will create a file called ie.job on c: that you can then use to run Internet explorer as the user given with the password given from the following command.
cpau -dec -file ie.job.
if that doesn't make sence let me know...
the *.job file is encoded so unless the user really wants to find the password, they won't be able to without some serous work.