internet connection sharing


dear friends i m running a cyber with 10 pcs and reliance wimax conn with static ip the problem i face is when my main pc (connection sharer ) goes off my other pcs cannot access internet i had heard about nat routers which share one static ip with pool of internal ips ( ....... and every pc gains seperate access to net so that if any one pc fails the connection on other pcs are not affected,,, if any one knows details about how to use nat routers to share the internet conn pls let me know thanks in advance pls specify any such routers model number and name