I play roller and ice hockey. Inline and ice skating is only slightly different as the skating stride is very similar. By slightly different, I'm referring to the friction and stopping motions. However on sport-court, you can "hockey stop" just the same but it takes more distance.
If you're doing speed skating, I think you'd have to take friction into serious consideration. Training on land (roller) will greatly help you with the power in your strides. You'll still have to work with those high-speed cross-overs though - and you can only do so on a large ice surface. Pro ice hockey players go with inline during the off-season to help keep in shape all the time. The friction makes it that much harder on your quads and is very beneficial.