With Introversion's cult-hit Darwinia being set loose upon XBL in the form of Darwinia+ (which includes the game proper as well as the multiplayer strain), I figured now to be as good a time as any to share the results of some searching I did on the musical front.
In the first, Darwinia's music (not yet sure if 'Multiwinia' has its own tuneage) can be purchased direct from the proverbial horse's mouth (http://www.introversion.co.uk/darwinia/extras/soundtrack.html); an unused track can be found here (http://www.introversion.co.uk/darwinia/extras/other.html) (note: the filename is incorrect; it is not DMA-SC's 'Visitors from Dreams', but rather an original composition from Introversion's chief 'sound guy', Alistair Lindsay).
The actual OST was ripped some time ago by Grawl (http://www.gamerips.cjb.net/), and can be found at among other places:


http://downloads.KiloHotelinsider.com/game-soundtracks/album/darwinia (just reverse the phoneticization)

Note: the track numbering therein is different from what appears to be the official version on the abovecited Introverion page, which I have reproduced here for ease of reference:

Visitors from Dreams Excuses Faces of a Fashion Pain Fade Down Impact of Silence Schroeders Failure (which I suspect to include a posessive)

The music for Uplink: Hacker Elite (http://www.introversion.co.uk/uplink) can be found here (http://members.multimania.nl/uplink/downloads.htm).

Thank you for Uplink, link!