KD,
I asked exactly this question about 18 months ago and got the same answers Mac and FJJP have given. If you don't use Outlook as a mail client I think there might be other options, but if you're locked into it like I am (work reasons) then I think there's no elegant solutionunless you set up a server of your own.
I use Mailwasher to filter the crap and have all Outlook on both my computers set to leave messages on the ISP's server. When I've got them both synced I tell Mailwasher to delete all messages.
It's a bit clumsy but it works ok in a home environment.
AA