If you sync your Palm via iSync to use iCal for your Date Book items, you also get your Palm To Do items synchronized into iCal as well. The problem with synchronizing iCal with the Palm Date Book is that iCal has an equivalent of the Palm "categories" in the multiple calendars it can have, but Date Book is the one Palm app that doesn't have categories. The iSync conduit deals with this by synchronizing all of the Palm Date Book items into one iCal calendar. This isn't really a problem, since they were all in one calendar on the Palm anyway. However, the Palm does have categories for its to-do items, and iSync dumps them all into the same calendar that you chose to put all the Palm Date Book items into. This makes using your Palm to-dos in iCal not much fun, unless you don't have very many.
I knew that although iSync will sync events and to-dos on the Palm into only one iCal calendar, it can sync multiple iCal calendars onto the Palm. I used this to sync a subscribed calendar to my Palm. But then I tried taking a to-do that was in my "Work" category on the Palm and moving it (in iCal) from the "Home" calendar (the one with all the Palm items in it) to the iCal "Work" calendar. I went into iSync and added the "Work" calendar to those synchronized to the Palm. When I synchronized again, the item remained in the Work category on the Palm and changes on the Palm were reflected in the item in iCal without disturbing the category there.
So, what I did was to create iCal calendars for each to-do category on my Palm. Then the tedious bit was to change the calendar for each to-do in iCal from "Home" to the one it was on the Palm. Once this is done, you only then have to do this for new items created on the Palm. Go into iSync preferences for your Palm and select to sync all these new calendars with your Palm. Now you can un-check any of the calendars that are holding to-do items that you don't want to see. I have some lists that I don't need to see all the time. This then reduces the clutter in the iCal to-do list.
One drawback is that items created in iCal go into the "unfiled" Palm category, but once you categorize it on the Palm, it stays there. Also, new items created on the Palm go into the "Home" calendar (or whatever iCal calendar you chose in iSync) for items created on the Palm. Once you move it to the calendar in iCal you want, it will stay there. Another drawback is that when you create a to-do category on the Palm, you have to create a new iCal calendar, and similarly, if you create a new iCal calendar with to-dos, you will have to create that to-do category on the Palm.
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