I'll leave this poll open until the end of June, by which time, probably there will be something new. Look in the sidebar of the Calendar Swamp blog for this poll. I've started the first Calendar Swamp poll to let everyone vote for their favorite Outlook-to-Google Calendar sync solution. More recently, SyncM圜al added full category based synchronization, which if I were still using Outlook would be a big thing for me. It's been out for a while - I first wrote about it in January 2007. MailShadow also does more than calendar sync, possibly violating Mace's First Law of Calendar Interoperability: Never use more calendar, or more interoperability, than you absolutely need. Scoble writes (in the same post as the Gcal complaints): 'When I enter a calendar item in Microsoft Outlook it instantly appeared in Google Calendar.' Ultimate price is unknown.

Cemaphore Systems's MailShadow for Google Apps also recently entered beta.Robert Scoble has some complaints about it. Google Calendar Sync, currently in beta.

Pricing starts at $29.95 per year per user with volume discounts