Amplifying analogue audio from an iPhone docking station
The LM386 is worth a little try: -



The above is a mono channel so you'll need to duplicate it for stereo. Note that the 0.05uF capacitor can be a 0.047uF (or 47nF) cap. The 10k pot will control volume and it needs to be a logarithmic type to get a realistic adjustment range. You can use a linear pot but you'll find that all the adjustment of volume is in the last quarter of the pot rotation.

I'm not sure what power supply you plan to use but running this amp from 9V (Vs) is typical and you'll get about 0.5 watts per channel into an 8 ohm speaker.

If you want something a bit more challenging there is this: -



And if you want more power there is this: -



Note that the TDA2030 can be used on its own to get 5watts to 10watts - look up the data sheet and give it a read.