Supported Versions: Magento CE v1.7.x, v1.8.x & v1.9.x and Enterprise v1.12, v1.13, v1.14
For a successful launch of your web store you will need to setup the following in your shopping cart and test your checkout.
1) Shipping Setup, whether UPS, Fedex or USPS and Weights.
* Your weights if supported by your POS system, can also be sent via eSync.
2) Taxes and Zones will also need to be setup directly in your cart.
3) Your Payment Method for collecting Credit card information. Contact sales for recommended Magento payment partners.
4) A Secure SSL for your domain will also be needed before going live when collecting credit card information.
Great Resource Magento Knowlede base: http://www.magentocommerce.com/knowledge-base