I replaced my cabin air filter because I drove through a couple of dust storms in our area. I removed the glove box by first removing the snap-on panel beneath the glove box (pulling straight down), then removed the 4+2+4 screws attaching the glove box. Disconnected the connector to the light and removed the glove box.
I purchased the filter from the dealer the part number was B7891-1FC0A.
The air filter is accessed through the oval opening covered by the white plastic cover. The white plastic cover is attached at both the top and bottom. The top latch is a small tab which fits under a small metal loop. It can be released by pushing down on the clip portion of the top latch. The bottom latch is simpler, it is a wide tab which flexes away (down) to release. The bottom latch is obscured by a cable with runs directly beneath the bottom latch. During removal I bent this bottom latch, because I did not know how it was configured.
One think I would like to mention is that the cabin filter is much wider than the opening. One must flex the ends of the filter to allow it to be removed or to insert the new filter.
The next time I will try to remove the filter without removing the glove box (now that I know how the latches work).
Here are some pictures: http://www.flickr.com/photos/14104449@N02/
Hope this is useful