I've seen so many questions asked about this the past week I figured I'd offer up this primer. There's much more at the link.
I'm also currently looking for a good guide for polling worker procedures and laws. I work the polls in RI and have the manual they give us, but I'm looking for the equivalent online resource (this will vary a lot from state to state) to share with everyone.
Just edited to add the RI statute covering observers below. (they're called party runners, checkers, and watchers here)
http://www.verifiedvoting.org/article.php?id=5194General Rules and Guidelines for Observing at Polling Places:
1. Make no contact with any voter inside the polling place.
2. Wear no political gear or buttons, nor partisan insignias of any kind. Do not wear candidate buttons, candidate t-shirts or candidate hats. (DO WEAR your TechWatch T-shirt!) Don’t carry or distribute materials which may have partisan or candidate information. Keep to this rule even if credentialed by a party or candidate.
3. Remember that the election judge or poll worker is in charge, and can decide where you are permitted to sit or stand, and how many observers or poll monitors can be in the location at a time. They also may decide whether you can be permitted to come and go, or switch off with another poll monitor.
Observing the Polls
Prepare in advance for observing at the polls:
1. Find out what type of equipment will be used by going to this web page:
http://www.verifiedvoting.org/verifier/ 2. Familiarize yourself with the method of operation of the equipment. See the “Full Information Sheet” for the voting technology you will encounter, included later in this guide.
http://www.rilin.state.ri.us/Statutes/TITLE17/17-19/17-19-22.HTM 17-19-22 Party checkers, runners, and watchers. The officers required to furnish and equip any voting place shall also provide a table in the room where the voting is conducted, outside the enclosed space near the first bipartisan pair of supervisors, at which a representative of the republican party and a representative of the democratic party, bearing credentials signed by the proper ward or town committee chairperson, shall be allowed to sit for the purpose of keeping track of those who are voting, and these representatives, who shall be known as "checkers," may be changed during the day. A representative, known as a "runner," of each of the parties shall be allowed to come to the table at frequent intervals for the purpose of taking whatever list or memoranda the checkers may wish to give the runner. A representative of the republican party and a representative of the democratic party, bearing credentials signed by the proper ward or town committee chairperson, shall also be allowed outside the enclosed place to observe the voting and assist the checkers, and these representatives shall be known as "watchers." The watchers and any election official shall have the right to challenge the right to vote of any person offering himself or herself as a voter.