I have an original Creative ZEN X-Fi, and it is brilliant. A lot of reviews say the X-Fi2 isn't as good as the original X-Fi though.
It cannot be used with an iPod docking station (or one that has an iPod slot), because, well, it isn't an iPod. The only way to connect it to a speaker system is using a 3.5mm to 3.5mm jack (such as http://www.amazon.co.uk/3-5mm-Stereo.../dp/B00077DC3S), or using an FM Transmitter.