Google has announced that Google Checkout will be retired effective November 20th, 2013:
http://support.google.com/checkout/sell/answer/3080449
Until that date, buyers can continue using their Google Wallet accounts to pay sellers using Google Checkout, but Google has already closed Google Checkout to new seller enrollments by now. In response to this news, we will be upgrading our integration with 2CheckOut to start fully supporting cart checkouts with 2CO via E-junkie's standard Add to Cart and View Cart buttons; Development has already completed this upgrade, which the rest of our staff will be testing this week to recommend any final tweaks before we take it fully live for everyone before Nov. 20th. Please see this post in our Service Status & Updates subforum for further details:
https://www.e-junkie.com/bb/topic/6608
While Google will be offering a new payment service called Google Wallet for Digital Goods, we discovered the only thing it has in common with Google Checkout is the name "Google", so adding support for it would be much the same effort as adding support for any other new payment processor, starting from scratch. Considering the limitations of this new payment service, we decided to prioritize upgrading our 2CO integration before we tackled Google Wallet integration. We do also plan to eventually support Google Wallet for Digital Goods, and we have some ideas about how we might even be able to support tangible and other non-digital products with that, but we would not be able to add support for it before Google Checkout is deactivated.