Untangle is an opensource great solution for building your own router LAN or router Wireless.
Untangle has greats features, it is really easy to use and almost pre-configured with captive portal.
The Untangle Server gives you a simple way to protect, control, and monitor your computer network. It delivers the technology you need to protect from threats such as viruses, spyware, and attacks. It protects productivity by controlling illegitimate web surfing, and gives an in depth view of network activity. All this in a single usable interface. Reports provides clear, concise reports about network traffic and policy violations. With this information you can spot problems related to viruses or spyware and also monitor illegitimate user behavior, such as web surfing or instantmessaging. The Untangle Server runs on a PC located between your Internet connection (cable/DSL modem, etc.) and your computer network switch. It can either replace or complement an existing Router or Firewall.
And yes, it has an awesome "Application Store" within a lot of free, apensource and commercial applications ! I definitely suggest to try it. I was on smoothwall or IPCop, but this ditribution is really really awesome.