Problem is, them cassette things don't recharge the Ipod, therefore you have to remove it regularly to charge.
I know this is about cheapness, but for a relatively cheap amount of money, you can grab yourself an Ipod compatible cable that leads straight out of the back of the HU and into the Ipod. You then need to spend something between £10 and £15 on a little adapter than downgrades the radios 12V supply to a 5V supply allowing you're Ipod to charge as you listen to it! Also allows you to use the CD Changer funtions just like having a multidisc changer.
Good thing about these is, you can make them reappear from the back of the HU to almost anywhere on the car, i.e. under the steering column for easy reaching or into the glovebox for security.
£74.97 .. for the Ipod carkit off of a website called Ipodcarkitdirect .co .uk .. I can't post URLs until i've posted 15 posts!
I don't think thats terribly bad. Also try Ebay for a chance of grabbing an even better bargain.
Hope this helps someone!