For salmon your going to need to head the Duluth, MN area on either the North Shore streams or the South Shore streams of Lake Superior like the Brule River. Streams on the north shore and south shore are open for fishing in April.
If you want trout, then you could possibly head to SE Minnesota, basically east of the city of Rochester. Whitewater River State Park and it's tribs are good bets for that. Depending on where in St. Paul but you could get to a good fly fishing stream in less then 2 hours. There are some streams directly east of St. Paul over in Wisconsin like the Kinnickinnic River which are fairly close.
As for books I like Humphrey's book on Minnesota and Wisconsin Trout streams. I still use it alot for exploring. The authors give you just enuf for you to try it on your own. It's a good read as well.
http://astore.amazon.com/minnesotaflyf-20/detail/0881504971/002-2559010-3464834
Good luck and welcome to the forums!