I suppose you want to publish and access your applications/websites from LAN; probably as virtual directories under the default website.The steps could vary depending on your IIS version, but basically it comes down to these steps:
Restore your "Default Website" Website :
create a new website
set "Default Website" as its name
In the Binding section (bottom panel), enter your local IP address in the "IP Address" edit.
Keep the "Host" edit empty
that's it: now whenever you type your local ip address in your browser, you will get the website you just added.
Now if you want to access any of your other webapplications/websites from LAN, just add a virtual application under your default website pointing to the directory containing your published application/website. Now you can type : http://yourLocalIPAddress/theNameOfYourApplication to access it from your LAN.
Other answers are basically right, thanks to them I was able to restore my default web site, they're just missing some more or less important details.
This was the complete process to restore the Default Web Site in my case (IIS 7 on Windows 7 64bit):
open IIS Manager
right click Sites node under your machine in the Connections tree on the left side and click Add Website
enter "Default Web Site" as a Site name
set Application pool back to DefaultAppPool!
set Physical path to %SystemDrive%\inetpub\wwwroot
leave Binding and everything else as is
Possible issues:
If the newly created web site cannot be started with the following message:
Internet Information Services (IIS) Manager - The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)
...it's possible that port 80 is already assigned to another application (Skype in my case :). You can change the binding port to e.g. 8080 by right clicking Default Web Site and selecting Edit Bindings... and Edit.... See Error 0x80070020 when you try to start a Web site in IIS 7.0 for details. Or you can just close the application sitting on the port 80, of course.
Note: I had to recreate the Default Web Site, because I wasn't able to even open a project configured to run under IIS in Visual Studio. I had a solution with a couple of projects inside. One of the projects failed to load with the following error message:
The Web Application Project is configured to use IIS. The Web server 'http://localhost:8080/' could not be found.
After I have recreated the Default Web Site in IIS Manager, I was able to reload and open that specific project.
Go to "Add remove programs"
"Turn windows features on or off"
Remove both IIS and WAS (Windows Process Activation Service)
Restart the PC
Step 2
Go to "Add remove programs"
"Turn windows features on or off"
Turn on both IIS and WAS (Windows Process Activation Service)
Note: Reinstalling IIS alone won't help. You have to reinstall both IIS and WAS