There are a lot of commercial lures available to target specks and look a lot like shrimp but none really come close to the action and aroma that a live shrimp gives off on the end of your line. The key to fishing with live shrimp is keeping them alive. Personally I like to use a 2/0 - 3/0 wide gap Mustad Ultra Point hook which gives great penetration and is resistant to corrosion in the salt water.
Keeping the hook small and hooking the shrimp through the tail or or through the horns works in giving the shrimp the ability to swim freely. A small # 8 or # 12 treble hook works equally well. Now the methods for fishing these are a little different as some prefer jigs, pop corks or just free lining.
When using jigs keep them extremely light in the 1/16th oz range or the weight will really get to the shrimp hindering the action of the shrimp itself. Jigging is usually reserved for when the water gets a bit cooler and the trout head for a bit deeper water.
Pop corks seems to be about the all time favorite. There are numerous nosies corks/bobbers sold just for such an approach. The idea here is placing the bobber over the shrimp (usually 3-4feet down) and every five feet or so give a tug on the line which produces noise vibrations through the bobber (due to the beads or other noise makers imployed and splashing sound). If the trout are around they'll definately find your shrimp. The popping sound is also supposed to mimic a feeding fish which attracts the trout and other game fish to the vicinity of your frantic shrimp which if alive is going nuts do to the action.
Another popular way to fish is free lining the shrimp. The big key here is keeping your shrimp cool and lively for when they are ready to use. Keep ice with your shrimp on hot days to keep them lively and the water cooled down as this is the big key fishing free line. Put a small split shot on your line to keep the shrimp from swimming up -- some use beads above the split shot for noise and color attractant -- then just work structures and cracks and crevices. The shrimp will swim freely about enticing vicious bites.
There are differences of opinions on how much the noise draws them in but as a rule of thumb if nothing has bitten in about 20 minutes its time to try a different area, between the smell of the shrimp and noise of the bobbers the trout know whats there if they're around.
As for the shrimp? Bring plenty as everything loves to eat the tasty candy treats -- cast nets can be a cheap effective way to get them (as long as you know of a few good places that produce) or they are generally about 3.00 a dozen at bait shops.