Gaming Tools

Google Documents
I use Google Documents for all of my campaign notes. I share out all of my house rules with the players and then have the players post electronic (PDF, Word, etc) versions of their character sheets in Google Docs as well. I create a new Google Doc with a picture of the monster for each encounter and then in the session I share the doc with the players (or give them the public URL to the Google Doc). All the players have laptops at the table and we run a Yahoo Conference. I drag the URL into the Yahoo Conference and then the players click the link, revealing the picture. I also pre-roll all Knowledge checks and then include that information in the Google Doc so that when the players view the pic they also see the info they know. If there are any special effects, like Gaze effects, I also have a line in the doc that says "All players make Fort saves".

Remote Gaming
Brian (my Cavernia co-creator Brian) moved to Georgia and plays in my current Pathfinder campaign via webcam and a voice conference. We post the camera near the battle-mat so he can see everything pretty well. He also maintains a Google Spreadsheet showing the dungeon floorplan as I describe it. We sometimes take pics of the tabletop with our camera phones for future reference.

Battle-Mats & Blocks
We tried various things. We had a blue gridded battle-mat but it was always stored folder so there was always an annoying crease down the middle. We also use 1" blocks that Brian made by cutting 1"x1"x8' lengths down to 1" blocks. He then painted most gray and some black. We find that the gray blocks can serve as walls in a dungeon, 2x2 make a wagon, 1x2 makes a horse, you can stack them to resemble pillars or put under a flying PC or monster. They can be trees or boulders, or virtually anything else you can think of. We use the black ones as doors when we are using the gray ones as walls.

We are currently using a glass table-top laid on top of a large gridded piece of paper. We use dry-erase markers to lay out the dungeon or encounter areas and sometimes overlay that with a battlemat for special encounters when we don't want to erase the dungeon (because the PC's are returning to it later).

Google Sites
I use a Google Site for my current Pathfinder Beta campaign. I have all of the house rules as Google Docs embedded in the Google Site pages. There are some nifty tools that work with Google Sites and you can embed Google Gadgets.

I'll post some more notes on tools I am using/have used in the past.