You can find out detail instruction from  [url=http://skp.mvps.org/liveweb.htm]LiveWeb - insert and view web pages real-time.[/url]

The following information are copied from the above web page:
[b]Download[/b] one of the following file first:
PowerPoint 97-2003 users: [url=http://skp.mvps.org/downloads/liveweb.zip]Click here [/url] (zip) or [url=http://skp.mvps.org/downloads/lwsetup.exe]here[/url]  (setup)
PowerPoint 2007 users: [url=http://skp.mvps.org/downloads/livewebfor2007.zip]Click here[/url] (zip)

1. Extract the contents of the zip to a folder.
2. Launch PowerPoint.
3. Click on Tools | Add-ins to bring up the add-ins window.
4. Click on Add to bring up the 'Add New PowerPoint Add-in' dialog box.
5. Navigate to the folder where the contents of the zip file was extracted and select 'LiveWeb.ppa' and click on OK.
6. You might be prompted with the macro virus warning. Enable the macros. When the Add-in is properly loaded, it will display a 'X' against the add-in name.
7. That's it. You have successfully loaded the add-in. Now put it to use.

Usage:
1. Click on Insert | Web Pages...
2. Enter the list of web page address that you wish to create.
3. Provide the additional info required.
4. LiveWeb will create slides with web browser controls embedded on the slides
5. Run the slide show.
6. The web pages will be displayed during the slide show and refreshed at real-time.
[img]http://skp.mvps.org/images/lw0001.jpg[/img]

[b]Note:[/b] If you cannot load an add-in in PPT2000 or later then check the macro settings (Tools | Macros | Security), if this is not set to at least Medium - the add-in won't load.

    To resolve this...
    1. Select Tools | Macros | Security on the security level tab, check MEDIUM.
    2. Click on OK
    3. Now load the Add-in as per the instructions.
    4. Once the add-in has been loaded you can set the Security level back to HIGH