Overclocking is a process not just a simple yes/no answer. If you shoot for just a simple "give me some numbers to put in" you're probably not going to get a fantastic result.
The guide below is an excellent and (believe it or not) very concise guide that will walk you through how to get your ideal overclock and make sure it's safe and stable. Plan on spending a few hours, but know that you'll understand just how far your cpu can go on safe voltages with safe temps.
Give this a shot and let us know how it goes. Just don't exceed the voltage limitations (probably don't want to go over 1.4v for your cpu and definitely don't go over 1.65v for your memroy), make sure your temps are within your comfort zone, and enjoy!