how can i increase my screen resolution from 1024x600 to 1024x768

The maximum resolution depends on your hardware - it can't be increased passed the maximum limit of the hardware. If you have a netbook with a 1024x600 screen resolution Metro apps will not run (but desktop programs will still work). 

You can try this modification to allow higher resolutions on your netbook:
http://www.netbooklive.com/how-to-get-better-resolution-on-your-standard-10-inch-netbook-2772/
 






For more info on Windows 8 Consumer Preview - FAQ page:
http://windows.microsoft.com/en-US/windows-8/faq
 
Windows 8 Consumer Preview main page:
http://windows.microsoft.com/en-US/windows-8/consumer-preview


Minimum System Requirements listed for the Windows 8 Consumer Preview:
1. Processor: 1GHz or faster
2. RAM: 1GB (32-bit) or 2GB (64-bit)
3. Hard disk space: 16GB (32-bit) or 20GB (64-bit)
4. Graphics card: Microsoft DirectX 9 graphics device or higher
5. To use touch, you need a tablet or monitor that supports multitouch
6. To access Windows Store and to download and run apps, you need an active Internet connection and a screen resolution of at least 1024 x 768
7. To snap apps, you need a screen resolution of at least 1366 x 768