I found a fun way to show the party their progress in KM exploration.
I got the map pack from Paizo. I then got some pads of Post-It notes. I took the top Post-It off a pad, stuck it on a hex on the map, and folded the sides up so I had a hex-shaped Post-It template. I then put the template on top of the pad and used scissors to cut along the template. I now have a pad of Post-It hexes. I then covered the map with these hexes.
Every time the party explores a new hex, I remove the Post-It hex cover, revealing the map hex by hex.
One issue with this is that it makes the map hard to fold, so I just covered half of the map with the Post-It hexes and leave it folded in half. As each hex is explored, I move that Post-It hex to the back side of the map.
Easy way (I use for the Kingdom building):
Buy some transparent gift paper a few paper clips and some folio-pens
Cut the gift paper to the right size (my was as board as two maps), use the paperclips to fix it on the maps (could also put them together with some tape on the back), use the folio pens to write.
With this you avoid possible mistakes while laminating it and you can also easily remove the "folio". :)
During the first exploration I gave my players a hexpapaer and told them to draw their own map :)
Meanwhile they hired the gnome explorer and bought the first two maps from him, so they know the topography but not the encounter :D
I laminated mine, and for the first map we used card stock cut into hexes and affixed with sticky-tack, and dry erase marker for the later ones.
I've run two groups. For the first I did the same a Courtney! - I laminated the big maps and covered them with little hexes that I pulled off as they explored. For the second group I laminated small, page-size maps and used expo to cover them, erased the expo as they explored. However you do it, it adds a fun dimension and sense of discovery.
Since my group plays online via Skype and MapTool, I took the map out of the PDF and layered a black layer over it in GIMP, then saved it as a GIMP file for myself and as a PNG for the players. As they explore, I've removed chunks from the black and re-saved the image. So far there's a rather meandering line down along the forest border to the radish patch, then a fairly straight line to the kobold lair and Old Sycamore, and a chunk cut out sideways leading to the gold mine. My group isn't all that great at stopping and exploring an entire hex, heh.