This tutorial is very easy to follow, make sure to follow the steps for results.

**This doesnt not work if Nitdroid is installed
1. Open App Manager
2. Find " Enhanced Linux Kernel for power users"
3. Find Qcpufreq
4. Install both apps ( during installing linux kernel you will get a notice, accept it. Dont worry, it backs up your original Nokia Kernel while installing)
5. Reboot the n900
6. Power on the N900, navigate to the Qcpufreq app.
7. You will see the original limits have changed. Click on options bar, and click on enable overclocking option.
8. Thats it! You can now easily overclock and underclock without a hassle.

** Make sure you dont have Nitdroid or multiboot or nitdroid kernel installed.**
Cheers. This tutorial is mainly made for noobs like me.