For the trout fisherman this should be a natural progression as these fish live in streams and rivers too warm to hold trout, yet they share many of the same habitat preferences except for water temperature.
There's been a lot written about smallmouth bass, so I'm not going to get into it too deep here. A quick search on the web will yield much information or better yet, reading through one of the many books on the subject
Keep your skills honed, your tackle from getting dusty and most of all, enjoy the great fun these hard fighters will provide through the summer and fall.
Some suggested reading: Fly-Fishing for Smallmouth
Fly Fishing for Smallmouth Bass
Smallmouth Strategies for the Fly Rod
How to Catch Smallmouth Bass