@alehawk:
Will this software work with 3 LAN adapters?
Yes, it will work with many more than 3 NICs.
@alehawk:
I mean, I want one to connect my ADSL modem, and two wired adapters plus one wireless.
Will it work?
Yes, provided you use supported adapters. Most (but not all) NICs that have been around for a while are supported. The range of supported WiFi adapters is rather smaller.
@alehawk:
The adapters configuration can be found after installing the soft via http?
Generally you need to configure one NIC as LAN and then the others can be configured by web GUI. Installation and configuraion documents can be found at http://doc.pfsense.org