Since updating to iOS 5 I figured I would give the whole iCould thing a go for my contacts, calendar and mail. The only problem here was that exporting my Google Contacts and importing the into iCloud was that everything I read said I need to use iCal / Address Book to get them across. I ended up using Sunbird to transfer the Calendar across, and came across these simple instructions in MacRumors forum.
Requirements are Gmail Account and a valid iCloud account (Apple ID)
1. Go to your Google Contacts
2. Click the More > Export
3. Choose the group or all of your contacts you wish to export, whichever you prefer.
4. Choose vCard format and click the Export button.
5. You will now have a contacts.vcf which has been downloaded to your computer. Put it on your desktop if you prefer.
6. Rename contacts.vcf to yournamehere.vcf (example: justyn.vcf)
7. Log in to iCloud.
8. Click Contacts
Important Note: Make sure there are no contacts listed here before importing or this may not work. The page needs to be blank.
9. Drag the .vcf file into the window under All Contacts.
The page will highlight with a blue rectangle when you drag the .vcf onto it. Wait a little bit. (It took about 8 seconds for mine to import. I only have 136 contacts though.)
On your iPhone, go to Settings > iCloud and make sure Contacts is listed as ON.