If you are talking about making a link that goes directly to the app in the market on an Android device, yes, just append the Package Name to the market://details?id=
or market://search?q=pname:
to create the link. In your example above the Package Name is: de.schildbach.oeffi
.
If you don't know the package name you can get it from AndroLib. It's a pain because their pages are so busy but if you can't find it just do a text search for "Package Name."
Just to be clear this link format only works when clicked on and Android Market enabled device.
Update: Yes. You now access the full Android Market on the website, and when you use the link format that therefromhere mentions in his answer (with http://market...), users clicking it on their phone will be brought to app in the market and users clicking on it on the web will be brought to the app's market web page.
Edit: No. The Android Market can only be accessed on Android Devices (more specifically only Android Devices with the Android Market Enabled).