Charset issue in body of Email

I have a Charset issue in which the HTML file is not being displayed properly in the Body of an email. Senario: I have a email blast program that was written in C# that displays a HTML Letter in the body. The problem is that when I send the email to someone that has a yahoo or hotmail account there are strange character being displayed in the letter. I am not sure what the program is doing because I do not have the source code. We have a VB script program that handle email blast also and it gives us no problem. I would like to rewrite this program in C#. I have a program written in [login to view URL] but I would like for the program to be written in C#. Does anyone understand what is going on with this process in .net. I need a sample program that I can use in C# to display a html letter. Open to bid nothing in stone. I have the example of [login to view URL] code that works. But I need a example written in C# ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform C#/2005 Window Environment