If you are really interested in doing this, there's not quite enough information in this article to pull it off. I would recommend reading the following link from Codeproject.com: http://www.codeproject.com/cs/miscctrl/exposingdotnetcontrols.asp
If you use the techniques outlined in the CodeProject article with Chris Sell's ComRegisterFunction/ComUnregisterFunction code you should be off and running!
Some important things to remember are:
1) Use the ComRegister/Unregister stuff!
2) Make sure to generate your assembly with a strong name and add it to the global assembly cache (gacutil /i)
3) I find I need to add the [ClassInterface(ClassInterfaceType.AutoDual)] attribute to my control for it to work.