Pretty simple, but pretty lame. They don't look nice, but you can see the title of the To Do at least.

Here's how:

In Leopard, iCal and Mail share all their to dos. But only some of them will travel with IMAP-- and only those things that travel with IMAP (such as your Notes) can be read on the iPhone.

Only "Mail Calendars" will follow your IMAP. These "calendars" are strange beasts. They are visible in iCal, but they don't take events-- only to dos. You can create them in Mail, and after you've done so, you can create more through iCal.

I have come to think that the overcreation of calendars is similar to oversorting your email, so I don't mind jamming all of my To Dos into one calendar.

So all this is a pretty nice stopgap, but I sure hope a juicy iPhone update comes soon.