By way of the USC Interactive Media Division's weblog, I discovered the Node Explorer v2, a location-aware, embedded-Linux handheld device that provides contextual information (maps, audio annotations, etc.) based on your current location. The twist? As opposed to consumer-based urban references such as restaurants, wifi hotspots, etc.- the waterproof, wireless, touchscreen enabled, card-sized Node Explorer is geared more for assisting site and visitor management at parks/national monuments/etc.- basically wide-open spaces that would normally require guided tours. The entire solution includes the Explorer, the Node Dock (for updating devices with new contextual info and recording back a visitors' trip data for analysis, as well as the obvious closed-loop monitoring of visitor admission/registration that becomes possible with such microdevices) and the Node Engine- a software platform for both monitoring visitor behavior as well as updating and managing the content that's provided to the handheld devices.
Considering the crappy (but oh-so-promising) experiences I've had with CD and RF-based physical tour guides, I'd like to try wandering around Yosemite with one of these little devices! Has anyone actually tried one of these out in meatspace?

We're trying to get a more simple solution to a broader public. And for free too:
http://www.podguides.net
(almost finished site version)
Nice! And duly re-blogged as of today... sorry about the lag there. ;)