Visual Studio has an integrated conversion tool in menu File > Open > Convert....
If your VB6 project is well structured and well commented and you are an expert in both languages (VB6 and VB.NET), you can give it a try, otherwise the conversion could become a nightmare. In any case you will have to fix many things manually after the conversion.
Googling Language Changes for Visual Basic 6.0 Users will give you useful links covering the differences between the two languages.
