I too use only Mac OS X at home at Windoze XP/Exchange at work with a BB.
PocketMac - www.pocketmac.net
works fine for Address Book and iCal, just forward your non-exchange email account to your BB through your cell providers BB web service while maintaining your BES connection for work emails.
Snerdware's Groupcal - www.snerdware.com
worked great to get Exchange Calendars and tasks to iCal before Tiger, but it still needs some work before I'll use with 10.4.3