There are several guides up here, a quick google check will turn up a number of names. If you want to do it yourself there are a few areas on the upper St. Croix that you can wade depending on the water levels, as well as, around St. Cloud on the Mississippi. The Snake north of the cities has wadable sections, as do a few smaller rivers south of the Twin Cities (Cannon, Zumbro and few others) that are wadable, again depending on water levels.

Hope this helps,

Kevin