An affected creature moves and attacks at a drastically reduced rate, as the slow spell.
It can only take a single move action or standard action each turn, but not both (nor can it take fullround actions).
Additionally, it takes a -1 penalty on attack rolls, AC, and Reflex saves.
A slowed creature moves at half its normal speed (round down to the next 5-foot increment), which affects the creature's jumping distance as normal for decreased speed.
In addition, any attack by the creature that would normally include poison (such as a spider's bite) does not do so, but all other effects associated with that attack apply.
For example, if an aranea subject to spiderbind cast a touch spell and then bit a creature, the attack would deal normal bite damage and trigger the touch spell, but the bite would not inject poison.
While you have this spell prepared, you get a +2 circumstance bonus on saving throws against poison.
Clerics of Eilistraee created this spell to help battle the many spiderlike creatures that serve Lolth.
Araneas, bebiliths, chitines, choldriths, driders, ettercaps, myrlochars, phase spiders, retrievers, and yochlols are sufficiently spiderlike to be affected by this spell.
For a more complete list of creatures that qualify as spiderkind, see page 30 of Underdark.