Trouble accessing the OS X Lion web server from other device
If you put it in the 

~/Sites

Folder then you have to navigate to

192.168.0.1/~USERNAME

Where you substitute your IP address and the username that belongs to the ~/Sites folder you copied your web app to.

To get it to just recognize the IP address without the username subfolder put it here:

/Library/Webserver/Documents

EG NOT the library folder in your home folder but the library folder in the root of the hard drive.