When I create an appointment on my Google Cal using a Mac or Windows EMClient when i view the same event after Sync on a IOS device any text i have entered in the Notes/Description shows in HTML format on iPhone but yet shows normally as i had typed on my Desktop EMClient
Unfortunately other applications are not yet able to display a formatted description for an event.
Fortunately the option to disable this is in your account settings. Go to Menu > Tools > Accounts and click on the Calendar tab for your Google account.