Ive got a nifty way for ya 
Im using this with PAL though, so if you are wanting to do it under NTSC you may need to check out if its supported. This is soo easy to set up, even my girlfriend could do it 
I have obtained a great little prog (written by the aussie legend arkay) called Crunchie. I have it setup & scheduled to convert my recorded tv dvr-ms to xvid in extremely high quality in the wee hours of the morning. The awesome thing about this is not just the space saving side of things (as usually xvid is anywhere from 30+ % better compression than dvr-ms), you can also get the converter to dump the files anywhere you like. Including Network shares and drives.
I have the converter picking up all dvr-ms files at 12am, then dumping them to a network share. Once the conversion has completed you can have the dvr-ms files automatically deleted so you can regain space back on your MCE 
Not only is it now easy to play any recorded tv file on any machine (as its just plain old xvid), the files are also small enough to successfully stream over a wired and even wireless network. The only downfall I have found is that you lose your meta description info and your recorded tv programs no longer end up in the recently recorded list.
Another huge benefit is because the recorded tv file is now xvid and not dvr-ms, DVB-T users out there that are experiencing problems where they cannot burn recorded tv files larger than 60mins can now get around these issues as the xvid files compress & burn well to DVD and you can now record a 60min+ show to DVD with compression and without problems

All in all A BRILLIANT TOOL and its Totally free.
One important thing to mention is the recordings are kept in very high quality. Dont be fooled into thinking this option is a downgrade from a great looking dvrms file to a crappy xvid file. Crunchie provides very high quality files. If you can tell the difference between the original dvr-ms and the xvid then you are a better man than I (or simply more fussier maybe) 
This a killer app to archive recordings and a great way of getting around the limitations of dvr-ms
A huge thanks out to Arkay
Crunchie can be grabbed for free from here:
http://www.xpmediacentre.com.au/community/showthread.php?t=1789
ENJOY IT !! I sure am !!
As far as Im concerned, this is the best app released since EPGRunner/ BladeRunner came to town.
M