Somme comments/corrections :
1. VirtualdubMod is more or less abandoned, even if there has been a bug fix release lately. As Virtualdub and VirtualdubMod are based on the old, outdated VFW (Video for Windows) mediaframework from M$, it can not work as a basis for a MKV editor (no support for VBR/VFR/etc.).
It is therefore not recommended to create or edit MKV files with VDM, the tool of choice is mkvtoolnix from http://mkvtoolnix.matroska.org , or better mkvmerge and the GUI mmg.exe.
2. Thanks to its very flexible file structure based on EBML (Extensible Binary Meta Language), MKV/MKA files can be very simple, or very sophisticated. Therefore i would prefer to call it the most powerful and flexible media container today, not necessarily the most sophisticated.
3. After installation of the matroska playback pack, every DirectShow based player (even WMP) should be able to play MKV files fine. MPC, TCMP or Zoomplayer are more advanced DShow players with better MKV support and thus recommended. For users with problems on their PC and DirectShow, VLC (Videolan), Xine or mplayer are nice alternative solutions, but can’t play all MKV files unfortunately (MKVs with Realvideo or ON2VP6 are maybe not supported then).
Christian
matroska project admin
http://www.matroska.org 
Quick Solution:
Everything you need can be found here: http://www.matroska.org (click on Downloads)
More info:
Probably the most sophisticated container today (even if it’s not the most widespread). Some of its features: open-source/royalty-free, multiple audio/subtitle tracks, variable bitrate audio, variable framerate video, streamable, dvd-style menus and chapters, fast seeking.
If you want to find out what codec a matroska file uses, use VideoInspector available here http://www.kcsoftwares.com/index.php?vtb
If you want to create, edit, or convert matroska files, use VirtualDubMod http://virtualdubmod.sourceforge.net
(VirtualDubMod can also losslessly transcode audio/video streams between the avi, ogm, and matroska containers.)
As noted on the Matroska site, alternate players such as Media Player Classic, The Core Media Player, VideoLan, or MPLayer are the preferred choice for mkv playback. It’s possible to play mkv files in Windows Media Player (or any DirectShow application) using filters (which are lower-level than codecs), but this is less reliable.
Stay tuned for more detailed instructions from ChristianHJW from the Matroska team!