ideally use a tripod but you can handhold if you are careful
Personally I would
Select a focal length of around 30mm (50mm full frame equivalent) and try to avoid scenes with close foreground objects (these will mess up the stitching unless you use a tripod and read up on nodal points)
select Manual mode (M)
dial in the aperture (probably between f/8 and f/11 to give large depth of focus)
point camera in direction of mid brightness. So if sun is bright in the left most shot and not as bright in right most shot point somewhere in the middle to take your exposure reading.
Half press the shutter button to activate the camera.
move shutter speed wheel until meter bar is on zero
You are now set and the exposure won't be recalculated for each shot as it would be in any of the other semi auto modes.
Keeping the camera level start taking your pictures (from left to right) with a 30-50% overlap in each frame.
Use some software to stitch ( I use photoshop CS3)
This was three shots, hand held with 24-105 set around 30mm