Multisite does not have cross-posting built in. you can do what you want with one of these:
http://wordpress.org/extend/plugins/threewp-broadcast/
http://wordpress.org/extend/plugins/multipost-mu/
Multisite does not have cross-posting built in. you can do what you want with one of these:
http://wordpress.org/extend/plugins/threewp-broadcast/
http://wordpress.org/extend/plugins/multipost-mu/