The memory can run in sync 1:1 with the FSB or you can use a divider(usually called "mem clock") to run memory at a lower speed. Depending on your mobo the settings should be 200,166,133,100 or DDR400,DDR333,DDR266,DDR200
Since the 4600 is already at 2.4ghz it won't have a lot of headroom for overclocking, you will likely get 2.6-2.7, 2.8 if your lucky. So you can start at like 210x12=2520, it should do that without increasing the CPU volts. Depending on what kind of ram you have, you will have to increase the volts and/or loosen the timings, or drop to the 166 divider.
Bump the FSB up a little bit at a time, testing for stability as you go, and add voltage to the CPU when necessary to make it stable. I wouldn't go over 1.55v