Snake hook:

http://www.beanfarm.com/store/agora.cgi?cart_id=7542939.6772&p_id=14000&xm=on

Or, a stick with a bend in it. Though those aren't always handy, as someone noted above.

If a snake just isn't moving from where you need to go, gently lifting it out of your way with a hook will do the job.