create unity plugin

How would one go ahead and create a unity plugin for both unity and unity pro? Until now I worked on a dll, but now I read that those plugins can only be used by unity pro users. How can I create a library of c# functions that anyone can access from any script?
I do have unity pro and a hint in the right direction might help me a lot!

Greets,
kiriri

Managed Dll’s, meaning the ones that only contain C#/UnityScript code, can be used in Unity and Unity Pro. What you mean is external dll’s that are e.g. implemented in C++. They can only be used with Unity Pro and they don’t work with webplayers. Hope it helps.