RetractableBridge

Hooray for new plugins. This one is from the same guy that did Portcoulissante, Captain Chaos. As with his other plugin, el Capitano gave a pretty good explanation of everything. So, rather than plagiarize the whole thing, I'm just going to link to it.

http://forums.bukkit.org/threads/mech-retractablebridge-easy-and-realistic-retractable-bridges.10659/

There are two things I want to highlight:

*The blocks underneath the bridge, not the blocks making up the bridge, are what need to be powered. They just need to have redstone under them to receive power though.

*The bridge will move South or West when it receives power and North or East when the power is killed. If you build a bridge and it's not working, this is likely the main culprit. You can either rebuild the bridge or just invert the redstone signal.

Enjoy!