[Andrew]

Aimee, as whpalmer4 says, you can use MobileMe for your husband's phone as well. However, keep in mind that if the two of you both separately make changes to the same item, the one that was changed most recently will be kept when the changes get merged, and the other change will be discarded. This includes things like reordering child tasks - if one of you renames a project and the other one adds a task to that project, then one of those changes (the one made least recently) will be discarded when the changes all get synced together.