SpeedyiTunes is an accelerator for iTunes. The program simply installs an icon in your task bar and claims to download iTunes music and videos up to 10 times quicker. In reality, you might find it's less than half of this although it depends on your broadband setup.
It includes speeded-up connections to shared bookstores, Podcast subscriptions and probably the most useful feature - radio streams. In fact, this was the best feature by far in that radio streams seem to be much more reliable and quicker with SppedyiTunes. The problem is however is that you never know whether it is genuinely speeding up the connections or its your own connection that fluctuating (known as bandwidth flapping.
However, if you are not satisfied with the speed of iTunes, SpeedyiTunes could be the solution you've been looking for - or at least - make your connections to the radio more stable.