In our post-grad Greek class here in Birmingham we are working the Didache this first half-term so I was looking to see what was available on the web. I hadn't realised before (or I'd forgotten) that CCEL have the Greek texts of Kirsopp Lake's Loeb edition of the Apostolic Fathers here:
Includes the Didache here:
All are searchable, though I've not tried the search yet. At first glance there are some errors in the Greek; I won't know just how extensive until I've spent a bit more time with it. It's all unicode too. For some reason I can't get my Internet Explorer 6 to show the font properly, though it looks fine in Netscape 7. Anyway, a useful contribution to the web. I should add that Wieland Willker also has an edition of the Didache available on-line, based on the critical edition of Funk / Bihlmeyer. This one requires you to download E-Greek font and there are no accents.
Update: I've looked at their What's New page and it seems that the Apostolic Fathers went on-line at CCEL in March of this year, so it is a new development.