The road layer in Google Maps has been turned on in Europe: What’s covered: The European Union, minus Estonia, Latvia, Lithuania, Cyprus, Slovenia, Malta, plus Istanbul and Moscow [and, um, Switzerland].
Directions between towns in these areas work, including for small ones; (just beware those pesky ferry rides). Address search doesn’t, nor does directions between specific addresses.
Comparing to Yahoo!’s and Microsoft’s European map offerings, Google Maps takes a solid lead on all fronts, in terms of satellite detail, road detail, and directions.
Individual countries’ mapping services can still beat Maps when combining road maps with address search and satellite images (in Sweden, for example, take a look at the very well executed hitta.se map service), and for Europe-wide address search and directions, ViaMichelin remains the champ. But among services with an API, I’d now choose Maps again for my mashup projects in Europe.
[Update 10:47 UTC> Christian Spanring has a good point about the timing of this release.]
[Update 15:18 UTC: The collective intelligence of the web points to address search and road coverage being a little uneven still. Some cities have full coverage and address search, others are spottier.]