Welcome to the Guild Annika! If you do find a way of scanning your hand drawn maps, we'd love to see them. As to digital software, there are a host of options available to you. Probably the two most popular here are Photoshop and GIMP (a free image manipulation program similar to Photoshop). I use GIMP myself, and if you don't already have Photshop, it's a good way to go. There are plenty of tutorials for both of these programs. Look forward to seeing your work.

Cheers,
-Arsheesh