iPhone to iCal sync resulted in shifted days in the copy

i did the sync on 6/23. 5/1 and prior days copied over to ical ok. 5/2 has events in ical that are not on my iPhone. 5/2 iphone events copied to 5/3 in ical. 5/3 iphone events copied to 5/4 etc...all the way through the to some events i have for next week. everything is shifted by one day in iCal, but are fine on the phone. any idea how to 1) fix this. 2) keep these shifted events from going BACK to the iphone the next time i sync. I log client work in these events. these are not birthdays. each event is money. i'm re-writing all this with paper and pencil. but would like to get this to work.