I'm thinking of getting an Apple iPhone, but I want to put all the brilliant third party software that is available on the www for it.

Thus my question is, if I get an iPhone and hack it so that it will accept these, will it void my warranty?

What would the ramifications of voiding my iPhone warranty be?

If hacking it would void the iPhone warranty, what are the alternatives to the iPhone, which do basically the same stuff, but also enable me to use this software?

I want a PDA phone that can organise me as well as play long MP3s (I record my uni lectures), however I'd also like to be able to do all the fun stuff such as the previously mentioned applications

yes it WILL void your warranty but I have hacked all 3 of my iphones and 2 have need ed service from apple and if you restore the software in itunes apple cant know if you hacked it in the first place so Its a matte of getting caught
if you do get caught apple will not service your phone if their is damage (ie not turning on or something that may be apples fault)
and I really dont know of any other phone that even comes close to the iPhone