To expand a little...
Although it seems to have taken root most firmly in New York, electroclash probably has its origins in Germany at the tail end of the 90s, with DJ Hell and his International Deejay Gigolo label.
The archetypal electroclash approach is playing ironic 80s style synthpop beefed up with a bit of techno and a generally style over content attitude. However, as with most genres, the perjorative stereotype (mostly) only fits the low rent bandwaggon hoppers: most of the major artists go well beyond these boundaries, bringing out a lot of the less obvious influences and producing seriously interesting music.
Some key artists, in addition to those mentioned above, include DJ Hell, Miss Kittin, Dakar and Grinser, Felix Da Housecat, Adult, Legowelt and The Hacker.
At the moment (circa 2003), electroclash looks set to collide with 'disco-punk,' assuming that the latter doesn't turn out to have been made up by the NME.