Hey Miltsack,
If I had some more info, may be able to help a little more. There's not really a course for flatpicking, but I have lessons that may help you. I think one way to get used to flatpicking, is to work on fills in between chords. I have these under bluegrass lessons, and let me know if this helps. Also let me know a little more about what you know, and there are advanced flatpicking lessons too.

Here are the links to the bluegrass lessons.

http://www.guitartricks.com/tutorial.php?input=832
http://www.guitartricks.com/tutorial.php?input=846
http://www.guitartricks.com/tutorial.php?input=869
http://www.guitartricks.com/tutorial.php?input=910
http://www.guitartricks.com/tutorial.php?input=917
http://www.guitartricks.com/tutorial.php?input=965

The 2nd, 4th, and 6th one, are strumming patterns with fills. If you want to work on your strumming too, just go through all of them. I hope this helps, and let me know if you need anything else.