Overclock Your Raspberry Pi - Squeeze More Power Out of Your $35 Computer

After recently purchasing my Raspberry Pi, I found many of the Linux distros to be slow and often sluggish. Unless you are using it as a pure media centre, you'll definitely want to try this method to make browsing the web and typing up documents a smoother experience. This method is totally free, involves no soldering and, if you stick with clock rates and don't tamper with the voltage, doesn't even void your warranty. I am in NO WAY an expert, especially with hardware, but this is very commonly done among the Raspberry Pi community and reasonably safe as long as you follow the instructions well.

Step 1: Requirements

You won't need much for this to work, unless you really want to push the Pi to its limits.

 - A Raspberry Pi
 - A Windows PC with Notepad++ installed http://notepad-plus-plus.org/download/v6.1.8.html
 - A small heatsink and thermal paste (If you're going to go past 750 or 800mhz)

The heatsink can be bought from Jaycar (if you're in Australia) or Radioshack (If you're in America) or where ever else you can find a  Pin grid array (PGA) heatsink. http://www.jaycar.com.au/productView.asp?ID=HH8580

Step 2: Create a Config.txt File

Once you have Notepad++, install it with the default settings and open it. Here you'll have to go to Settings>Preferences>New Document/default directory and tick the Unix checkbox that appears, rather than Mac or Windows. Once this is done, open a new file and type the following: 

carm_freq=800
gpu_freq=300
sdram_freq=450

If you're feeling bold you can adjust them a little higher, but if you're going to go to 900 you definitely need a heatsink as well as bring the GPU down about 50mhz to make up for the power being supplied to the unit.

Once this is done, save your file to the boot partition of your SD card as "config.txt". The boot partition will be the only partition that shows up on Windows usually(about 60mb in size) - if it doesn't show up, you'll have to put your config.txt on a usb and transfer it onto the SD card with a Linux machine like Ubuntu. 

Step 3: Finishing Up

If you bought the heatsink, now's the time to grease up your CPU and firmly press it down. Let the grease solidify a bit before continuing, so that it doesn't slide off. Once this is done, boot the Pi.
If it doesn't boot, or has a kernel panic, don't worry - just edit the config.txt file and bring all the values down a bit until it does boot. Remember the default CPU clock frequency is 700mhz. 
You should notice about a 15-20% increase if you run any benchmarks, more if you bought the heatsink and took it to 850mhz or 900. If you take it over 900 without a boost in voltage, it probably won't boot, and conservative old me isn't going to ruin my warranty by screwing with such things. If you run into any problems, then you can just wipe the config.txt file to get it back to normal.
Sorry for the lack of pics on the heatsink, I ran at 800 without one for a little bit but as soon as I get one (probably this weekend), I'll upload it.
You can do all this on the pi itself too, and just reboot it.
Good luck!