Yes, I know what you are talking about, but have you even put any effort into finding the part? You've been given advice to check bavauto.com and your dealer. Have you tried doing a quick google search for what you want?? A quick google search for "328i charcoal canister filter" showed me that BMPDesign in TX (I've ordered from them before - great bimmer parts company) says they have charcoal canister filters for E46s and X5's, so I imagine they will probably have them for your E36 as well....
Give them a call to see if they have one for your car. 800-648-7278
If all else fails, call your dealer....the parts department can certainly get the part for you and can probably give you advice on how to change it.
Replacing it should be as simple as removing the charcoal canister and replacing the old filter inside it.
Now go get your part and fix it.