[Disclaimer] I already know a converter exists, but it Exists for Linux and this is probably the first windows one to exsist without any need to install more software but instead by downloading and running.
I have created a texture pack converter for windows. It will convert most blocks and items over but it may need assistance with some. You will need to fix up the grass textures which will be grey and HUD will not be ported, same as other items like copper and steel.
Download Link: https://www.mediafire.com/?tld6fc71f6yysip
Feedback is appreciated i will try to update the converter as time goes. Feel free to modify the converter and redistribute it but link back here.