I've just remembered too - there's a game knocking about called "Tower" whcih is really good.
You can download it from
http://www.theunderdogs.org/
Try it - it'd about 5ish MB to download but when it's up and running it's basically a Tower sim where you can actually see the little planes as they come and go and taxi at one of the three airports provided.
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"Go around..I say again...go around"