Yes it's the same to your email.
Your paypal ID is your paypal email address.
The one you used when you are signing up in PayPal.
Some addition info for others:
Not only does PayPal use your email address and there's also something called a Merchant account ID which can be used in place of your email address for the "business" variable value in your item button code. I'm not sure about Premier Accounts but, if you have a Business Account, you can find the Merchant Account ID in your Account Profile settings under "My Business info". The Merchant account ID was developed as a substitute for your email address to prevent spam bots from harvesting your email address on web site pages that contain your item button code. The Merchant account ID is sometimes referred to as your PayPal Account ID Number.