I have just managed to link a working analytics account to a clients Google PPC account. This might sound pretty straight forward, but not when your clients PPC account already has an analytics attached that isnt in use, and they have another analytics account which is already full of data and needs to be added. Inspired by Simon’s somewhat incestuous post about Link love i thought I’d also share the love.
Ok firstly Log into your client account at https://adwords.google.co.uk and click on the analytics tab then:

1) If you do not have an Analytics account;

• click the Continue button to sign up for one – DONE

2) If you already have an Analytics account;

• Click I already have a Google Analytics account.
• Select the name of the Analytics account you would like to link to from the drop-down list
• Keep the checkboxes selected on this page, unless you are sure that you would like to disable auto-tagging and cost data imports.
• Click Link Account and the accounts are linked – DONE

3) If you find that there is an analytics account attached, BUT there is no data in there and the code is showing as not verified.

• Check your client site contains the same analytics code as the empty analytics account. If it is the same then the client should check if it is set-up properly and this should then start logging data.
• If the code on the clients site isn’t the same as the code in the analytics account;
• Call your client and asked them if they have access to the other analytics account,
• If they do, get them to set your personal Gmail address as an administrator or get the login to set it up yourself
• Once you are an administrator, log in to the clients analytics with your Gmail address and password
• Add the email used to access the Ad words account and copy it into the Users with access to profile section in the analytics account as an administrator in the analytics account and save it.
• To delete the empty analytics account;
• Call your Google customer service and ask them to delete the empty analytics account from the PPC account, as you can’t do this manually.
• Once you get an email saying this is done
• Log in to your Ad Words account at https://adwords.google.co.uk.
• Click the Analytics tab.

Click I already have a Google Analytics account.

• From the Existing Google Analytics Account drop-down list, select the name of the Analytics account you would like to link to *.
• Keep the checkboxes selected on this page, unless you are sure that you would like to disable auto-tagging and cost data imports.
• Click Link Account – DONE

Hope this explanation makes perfect sense!