I was just playing around with my phone and tried a trick and it worked.
If you want to get on Vodafone 3G even before it gets officially Launched, here is how it works
For Prepaid: SMS > ACT 3G and send it to 144
For Postpaid: SMS> ACT 3G and send it to 111
You will be charged as per your current 2G plan for now.
ENJOY 3G!
Remember this trick is exclusively brought to you by us.