The get_member() method returns a 2-d array. The first dimension to match to each pool name you passed in in the pool_list parameter. The "Disabling Node Servers" codeshare entry will query all pools, and then pass that list into get_member, and then enumerate through the 2-d array.
http://devcentral.f5.com/wiki/default.aspx/iControl/DisablingNodeServers.html
Click here
Look for the findPoolsFromMember() method. It calls a subroutine to get the 2-d array of members and loops through the results. Not sure if this is the "best" way, but it does work.
Cheers!
-Joe
Nimbostratus