I have it set up on my wife's phone and mine for shared calendars without having each others email on our phones. I used google calendar and have a separate calendar in google for each of us. I then set her google calendar to be shared with me (through google). I share my calendar with her (through google). I then use google sync on our blackberries. Since her calendar is shared with mine, I have the option in google sync to also sync her calendar to my phone (and she syncs mine to hers). When I make a calendar entry in my google calendar, it gets added to hers and vice versa. I think you can even set it up to give you an email notification when stuff is added. It's pretty slick!
I was going to suggest BBM Group calendar as well. My wife and I use it and it works well. Add something and it shows up almost immediately on the other BB.
You can then also use Lists within the group for other things. We use it for the grocery list so we can both add things to it anytime, and mark things off no matter which one of us goes to the store (just have to remember to clear out the list on each BB later).
I was going to suggest BBM Group calendar as well. My wife and I use it and it works well. Add something and it shows up almost immediately on the other BB.
You can then also use Lists within the group for other things. We use it for the grocery list so we can both add things to it anytime, and mark things off no matter which one of us goes to the store (just have to remember to clear out the list on each BB later).
We use honeydew for syncing our lists. I will have to look into BBM groups. I didn't even know that was an option!
