There are a few aftermarket products as well. I'll do my best to explain.

1) AstraSync.com / NotifySync.com - if you have Exchange, it does a good job at using the ActiveSync protocol to sync your data wirelessly using existing BIS plans. This is about as close to BES as possible if you have an Exchange server and don't really want to spend thousands....

2) ThinkPost.net sync - (our product) / syncing contacts/calendar/notes/tasks between the PC and the BB OTA - does not support email sync however - but you do retain your existing email address. This particular product does not require Exchange.

3) Google Sync - based on reviews, it's hit and miss for problems. However, it's free, so give it a shot first!! =)