Certainly, and I'll try to sum it up quickly.
1) In the US, your transition altitude is FL180, in Europe it ranges by country and can be as low as FL040 (4000ft)
2) SIDS and STARS in Europe explain everything and you fly it exactly the way it's written, in the US you are often radar vectored in/out from a fix off the arrival or departure. ATC will assign the altitude in the US, in Europe its written on your charts.
3) Some countries in Europe, such as Russia, measure altitude in Meters.
4) METARs and TAFs are different, such as the use of QNH, measuring visibility in meters as opposed to statute miles, etc, etc.
5) IFR clearances are extremely short in Europe. "Westwind 752, cleared to London-Heathrow via the BIBO7S departure, departure with Frankfurt Radar 123.456, sqwk 1234" In the US, you get the whole clearance read out: "Westwind 752 cleared to Chicago O'Hare via the Oberlin1 departure, Waterville transition, radar vectors to Dreyer then as filed. Climb and maintain 5,000, expect FL260 10 minutes after departure. Departure on 124.00, sqwk 0701"
6) In the US, you have approach, Centers, etc, etc. for ATC position. In Europe, its controls, radar, etc. for station names. They get upset if you refer to them as US ATC.
Thats a short list for you.... its a few differences but its not difficult to pick up or learn, and I highly suggest flying in both places!
Ian S. Crawford
WWA 752, CYYZ
VP Director of Cargo Operations, Europe
AOPA # 05034673