Google has announced that it will be merging its two payment options into one with Google Checkout now becoming a part of Google Wallet. Enabling user who are currently using Google Wallet to be able to make purchases on Google Checkout enabled websites.
If you are a current user of Google Checkout you account will automatically be merged by Google into Google Wallet the next time you login or make a purchase.
Google has also stated that it will be making Google Wallet a payment method for purchasing applications on the Android Market. All Google Checkout and Google Wallet users can now access online purchase history and payment information at the Google Wallet website.