At least not unless palmOne writes some Treo-specific drivers for it, since according to an anonymous tipster who tested palmOne's SD WiFi card with a Treo 650 he got his hands on, the card definitely does not work.
It's no secret that palmOne's SD WiFi card works only with their T3 and Zire 72 handhelds, but despite some earlier indications to the contrary, it doesn't look like the card'll also work with the new Treo 650 which is due out later this year.