What course work/requirement I need to be a web designer?

Hi I am a graphic designer with many years experience in the field as both in corporate America and as a freelancer. I have wanted to branch out into Web Design for sometime now. I am not sure where to start? Any suggestions/advice etc. Do I need to have a lot of software knowledge? I am very solid in Adobe Photoshop, Indesign and Illustrator. Where can I start?