Create a new C# project and open a new form in the designer (so you are looking at the controls, rather than the code).
Now open the VB form in the designer, and select all the controls. Copy them to the clipboard.
Go back the the C# form and paste the controls.
You will have to create all the event handlers again, but if you have existing VB code behind them, there are online code converters which may help:
http://www.developerfusion.com/tools/convert/vb-to-csharp/[
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http://converter.telerik.com/[
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Are the two I use.