Same problem here, Buick.
I have an iPad, an iPhone4s and a new iMac. I normally go to google calendar on my iMac to enter appointments. Those appointments all sync and appear with my iPad, iPhone and the iCal on my iMac. However, if I enter any appointments on either my iPad or my iPhone, they not only don't appear in my Google calendar, but they don't appear in iCal on my iMac. I've been round and round with various "fixes" I've found online but to no avail.
Like a fool, I should have resolved this last night when I called Apple Care about a problem I was having with my address book while trying to create a group distribution list. What I thought would be an easy walk through of how to do that, turned into a thrice transferred between departments at Apple and a stumped "expert" that took 90 minutes to finally resolve (I was doing everything correctly, it just wasn't working). By that point, I had no time to then ask about my calendar issues. For now, I've just been manually entering them (fortunately, I mainly add things to my google calendar than on my iPad). If I find some time today to call Apple Care again to see if they can figure out this problem, I'll post back here. But I mainly wanted you to know that you aren't alone in your problem!