Can I sync iCal between two iPhones?

I don't know if it's the sort of thing your after exactly but we organised with MobileMe to contain both our calendars and a joint calendar each with different colouring. We then sync both our Laptops and our desktop computers to MM and our iPhones as well we set the default calendar on my wifes iPhone to her calendar and mine to mine same with the Laptops and the desktop to a shared calendar. On the computers it comes up with all the Calendars but we can toggle them off so you only view one at a time and on the iPhone you can do the same by clicking Calendar>Calendars>(which calendar or all calendars)
So to summarise on MM we have three calendars
Shared
Me
Wife
This allows all the Calendar events by anyone to be edited by anyone and if i want my wife to do something i just add an event to the calendar using my iPhone but change the calendar option to her name so it appears in her calendar and in her colour if you are using the view all option

We have one MM account for the both of us xxxx@me.com

Ok i'll try the instructions bit now 😉
All this is done from the MM web interface

First we stopped the home computers syncing to MM

Then we set up two email aliases myself@me.com and mywife@me.com
that way we can each have an individual email address and a shared one as well
We then filter the email coming in so they go to a folder named for each of us or if it's sent to the main MM email account it stays in the inbox (though you can just leave it so all mail to both of you along with the main email will go into the inbox)
choose Actions(the little gear symbol)>Preferences>Aliases tab to manage aliases

For calendars you go to the calendar view
Then on the left click on the + symbol or right click and choose to create new calendar we created three "us" (for shared events), "myself" (for me), "mywife" (for my wife) and assigned a colour to each

on the iPhone
go to settings>Mail,Contacts,Calendars>Default Calendar>(appropriate calendar for each iPhone)
This means that when you create a calendar entry it will default to being in your colour
If you want to create a calendar entry for your wife when you add a new event there is an option to choose the calendar you add it to, once the event is added though you can't edit this afterwards.
The default view is to see all calendar entries for everyone if you just want to see your events open Calendar>Calendars then select the appropriate calendar to just view that calendars events the calendar will remember this setting for next time

Once this was done we re-sync'd the home computers to MobileMe and they picked up the multiple calendars and displayed the entries accordingly so no setup was required on them.

Hope this helps if you want me to expand on any points let me know as i tried to keep it as brief as possible while still providing a reasonable guide.

Not sure the only thing that would make life easier is if they add the functionality to have two push services running on a single iPhone but i haven't heard any mention of this happening. I know it sounds reasonably complex from my explanation but it took me all of ten minutes to set it up the only downside for you i suppose is that currently it only works for me because we share the one MM account whereas you have two which complicates matters