Nikon Reviews in a Nutshell

Good news for D90, D7K series, D5K series and D3100/3200 owners: finally an economical alternative for the Nikon GPS GP-1 has arrived!
Today (04/06/09) Promote Systems launched a new version of their GPS N-1 unit - called GPS-D90 - with a connector specifically designed for these two cameras. The GPS-D90 ($ 149) allows for instantaneous geotagging at a rather more convenient price than the Nikon GP-1 ($ 270) and can be bought - for the moment - directly from the Promote Systems online store.

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I have used this GPS on my D200 with very satisfying results, even in situations with a partially blocked view to the sky, either by heavy cloud or abundant tree coverage, such as in the tropical rain forest of Costa Rica.
The only difference between these two versions is the connection cable, since the professional Nikon camera line (D2, D200, D3, D300, D700) has a 10-pin connector at the front of the body, while both the D90 and D5000 have a dedicated connector at the left side of the body, covered by a rubber seal.

Connectors: Nikon D5000 with Promote GPS-D90 vs. Nikon D90 with Nikon GP-1

What distinguishes the Promote device from the Nikon is that it has a L shaped connector, which does not only save space (in the camera bag) but is also less vulnerable.
Although on the D5000 the plug inserts as illustrated in the above image (left), on the D90 it connects “upside down", that is to say: with the cable upwards. How about that for Nikon “design wisdom"?
All the other specifications of this new version are exactly the same as the one for the professional Nikons, a review of which can be found here.
For more about geotagging, visit the Promote Systems blog

See also:
Promote GPS 10-pin CA10 to D90-type CA90 connector conversion.
Geo-tagging Flickr images: the coolest game on (Google) Earth.
“Geotagging” with your Nikon. Review of the Promote GPS N-1.