[glchen]

I use the ebay Seller Manager add-on, which is free, and there it lists the email addresses for the recent transactions. I always copy these into my spreadsheet which tracks my sales, which I later use for tax purposes. (The emails are also in paypal.) Here's a snapshot of the Seller Manager.

Edit: To subscribe to the free Seller Manager, go to My Ebay -> Account -> Subscriptions. Then subscribe to the free ebay Seller Manager. (The Pro version may have a fee if you don't have an ebay store.)

Edit 2: Scrubbed the email addresses in the picture slightly to protect the privacy of those customers.