If you mean to say that you created a Class Project (e.g. the only file in your project is a file with .vb
extenstion) press CTRL + SHIFT + B (Build) then navigate to the folder where the project resides, go into the bin folder and there will be a dll with your projects name, that is your compiled class, now just add it to the man project.
If you mean to say that you created a class file inside of a web project, you dont need to worry about compiling it into a dll, it will be compiled as part of your project DLL then to reference it you would do:
[className] cn = New [className]();
Any methods or functions declared without private will be accessible by doing:
"The one language all programmers understand is profanity."