are you using MS Outlook 2003 or later? coz outlook 2002 has a lot of problems w/iphone syncing.
if you are using outlook 2003 or 2007(preferred), a few basic syncing points to check:
1. make sure you open Outlook at least once in the new user and create the outlook profile before syncing(just follow the wizard in creating the new account, and you don't need to input your e-mail if you don't use outlook for e-mail) .
2. tick the checkboxes in the itunes iphone contacts & calendar tab to make sure they will be synced.
3. look if you selected Outlook in the pull-down menus (make sure outlook is selected and not outlook express) for both calendar and contacts.
do these for both you and your wife's windows user profiles since each account setting is treated separately.
a good idea would be to back up your existing ms outlook data by selecting "import and export" from the file pull-down menu and select export to file. this way, if syncing screws up, you can restore your outlook database. or you can cleanly wipe all your mixed-up outlook data after a bad sync and restore from this database file if you choose to do so.
tell me how it turns out.
