I used my Weber propane grill to successfully smoke a pink salmon yesterday. It doesn't taste as smoky as what comes out of my actual smoker (all analog offset firebox barrel smoker) but it is still damn good, and tastes and smells like smoked salmon. It's a good method for when I'm just doing one fish at a time, not production smoking. It was a pretty big pink.
First I heated the grill up with all three burners and cleaned it. Then I made a foil pack of soaked pecan chips that was burner-sized, and poked a few holes in the top of it, slid the grill grate over, and put the wood chip foil pack on the "flavorizer bar" that goes over the burner. Slid the grill grate back on, turned the two right burners off, and cleaned the grill with oil. I also put some bigger wood chips and smaller chunks right on the grill grate on that side, also one of these wood-dust pucks I picked up a while back. I mostly kept the one burner on low or medium but I played with it a bit, depending on grill temp. Most of that wood stuff caught on fire at one point but I just blew it out and then it was smoking nicely. Temps were between 200 and 230 according to the grill top thermometer. I pulled the salmon when it was between 120 and 135. Good stuff.