The jQuery Mobile team has announced the release of Alpha 4 version which supports Windows Phone 7. Here is their announcement from their blog post,
Weâ€™re thrilled to announce WP7 is now a supported platform and has a solid A- experience. All core features work great on both WP7 and desktop versions of IE 7 (8 & 9 are close, but not perfect). Keep in mind that WP7?s browser is fairly close to IE7 so advanced CSS features like rounded corners and drop shadows arenâ€™t supported but the layouts and widgets all look great within the capabilities of the browser. Weâ€™ve added a polyfill to bring pseudo-media query support to this platform, which we plan to improve with a native media query interpretation at a later stage. We also plan to support the future upgrade to an IE9-based rendering engine on WP7 later this year.