I usually give my presentations with acroread. Sometimes it’s comfortable to walk around in the room but still be able to switch between the slides. Unfortunately neither acroread nor xpdf support switching with a mouse or any other pointer device. But there’s this nice tool called imwheel. It allows to map mouse buttons to keys, like mapping the mouse wheel to page-up/page-down. This is done with a file .imwheelrc in your homedirectory, looking similiar to this:
"AcroRead" None, Button4, Page_Up None, Button5, Page_Down
After starting the imwheel daemon you can now use the mouse wheel for switching between slides. For pointer devices that have only buttons you simply can swap mouse buttons with xmodmap.
xmodmap -e "pointer = 4 2 5 1 3"
Now you can use the left and right mouse button for switching. Simply turn it off again by executing:
xmodmap -e "pointer = 1 2 3 4 5"