Alternative to iPhone? Everything. But seriously.. the upcoming Palm PRE, HTC Touch Pro2 / Diamond2 (not mentioning previous versions while new ones appear on the horizon, but they beaten iPhone hard too), Blackberry Storm / Bold, Google G1/2, SE Xperia X1, Nokia N97, Samsung Omnia, I believe, are good examples.. These and all other high-end phones. iPhone isn't one of them but Apple did great marketing job so that people are comparing everything to it. It has a lot of advantages but it's not a high-end device.
It's a great phone, but not a great smartphone. But in the end, everything always depends on what you're looking for.
Some humor about iPhone and how others perceive it (wait 'til the very end after subtitles, hehe):
YouTube - Cell Phone Reunion
You might also want to consider this, hehe:
