I saw some hours ago at eBays a jerk selling instruction for resetting the maintenance-alert-feature (Sorry, i do not know the proper word for this thing in the display which tells you "....2145 km left to go to you BMW-Dealer to perform maintenance of your car"). And i thougt that this canīt simply be true, there MUST be a site which gives you these tipps for free....and i succeded:
http://www.bmw-style.de/homepage/tips_umbauten.htm
I found a lot of hints about resetting, about using the display for showing a lot of things (like the amount of fuel remaining in the tank, oiltemperature, airtemp......and so on). The tipps are for E30, E36 and E46 as well. Sorry for only-english-speaking members here :-((
My english is simply too bad, else i could try to translate some of the most desired hints....maybe try babelfish :-))