Sencha released a new version Sencha Touch with Windows Phone 8 support. But since it's an alpha, there are a few more things to do than what the release note says to get it working.

One thing I've noticed is that when you generate a new app with

sencha generate app Foo path/to/foo

and make the changes to resources/sass/app.scss according to the release note, compass compile path/to/foo/resources/sass fails complaining a font file is missing:

File not found or cannot be read: path/to/foo/resources/sass/stylesheets/fonts/pictos/pictos-web.woff

To fix this, copy the needed fonts to where it supposed to be:

cd path/to/foo
mkdir -p resources/sass/stylesheets/fonts/pictos
cp touch/resources/themes/fonts/pictos/pictos-web.* resources/sass/stylesheets/fonts/pictos/

The next error you'll see from compass compile is caused by the name changes to a few sass files in the framework. Long-story short, you need to change resources/sass/app.scss to the following:

and compass should be happy from there.

While you are at it, why not checkout the magical Windows Phone 8 theme included in Sencha Touch 2.2 alpha.