Hi,
Is there any difference in meaning between these two sentences when using simple present and present progressive? In everyday English, not really. Here are a couple of comments.
a) I look forward to your visit ! Could refer to my habit (eg Every year, I look forward toyour visit.)
b) I am looking forward to your visit ! Sounds more related to the present, to now. Also sounds to me a little bit more informal and friendly.
Clive