Using AOL ISP through Router

My client have AOL as ISP and have 1 desktop and 1 laptop together through Linksys Wireless Router, WRT54G, with 4 Ethernet ports and DSL/Cable. The router is setup as PPOE using AOL username and password. Status on the router shows CONNECTED. However both desktop and laptop cannot surf on any website using Internet Explorer or Mozilla FireFox. If I use AOL software through LAN/TCP/IP, then I am able to surf at any website on either laptop or desktop, but not both at the same time because of same username is logged in AOL software. How can I get both laptop and desktop to be surf at the same time?