In the event either the Internet, Twitter or each Occupy website should be taken down or be made otherwise unavailable (this is a strong possibility), contingency Communications Plans should be made and said plans dispatched via DM while we can still communicate to one another.
NOTE! Please make back-up copies of your work, preferably on another computer and/or a flashdrive - and use said backup on this other computer (one you haven't used for the purpose of communicating anything during the protest), to re-create your websites, files, etc, at another location and then dispatch the new URLS to everyone you can.
http://wiki.hacdc.org/index.php/Byzantium was invented with these sorts of communication difficulties in mind. A number of the engineers have expressed an interest in deploying a wireless mesh for /Occupy*/i protestors on-site.
You should also save OccupyTogether's Contact list, as well as any other data you deem important to use in the event the worse (no Internet) comes to pass, in this same manner.
You might clean up the old CB radios.. I have global communications equipment as a ham it would be good if the ham community would get involved if only for the safty of the large numbers of people gathering. These people can provide communications that will not be interupted. talk to your local ham opperators and get them involved. I will work on this in my area. FRS and GMRS radios work well for co-ordination, also.
If an encampment area is not within range of wi-fi hotspots, you might consider setting up a relay system using technology developed by DoogieLabs (http://icebox.doogielabs.com/thelab/node/10), which has been successfully deployed at OccupyDenver. This repeater system uses a satellite dish and wireless router, and can be powered, if necessary, by a 12 volt car battery for two days.