I have been accessing my MSDN ISO's using a little Utility called:

Virtual CD-ROM Control Panel for Windows XP 

Unfortunately it doens't really play that well on Vista....That said you CAN use it -with only two gotchas.

The first it must be run as administrator.

If you don't you will get the following error when you attempt to load the device driver. 

 

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VCdControlTool
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Cannot Open SCM : Access is denied.

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OK
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The second issue -and the most most frustrating is the drive that the CD-Rom Control Panel mounts is ONLY visible to the the Administrator context.....

This means if you launch explorer you can not see the drive the CD Control Panel just mounted. Even if you launch explorer "As Administrator" it doesn't see it (don't ask me why) but if you launch a command prompt (CMD.EXE) as Administrator it CAN see the mounted drive...and if you launch an instance of explorer from the command prompt it too can see the mounted drive...at which point you can install/copy etc from the ISO.