A .ogg (or .ogm) file is a video file with dual audio layers that can also include subtitles. To view these files you must use Windows Media Player, and download specific (usually DIVX) codecs which can easily be found through a search engine. .ogg files are usually of insanely good quality for their size. unfortunately, i've no clue as to how to convert them from .ogg status, and i am infact looking for ways to rip DVDs into .ogg files. however, that should at least allow you to watch them on the computer once you have the codecs.
.ogg is just audio file mate http://drn.digitalriver.com/product.php?id=76316&cid=267&SiteID=driverguide but if u still wanna convert it go there not sure about .ogm tho Dean