hi gidge!
There are .wav to midi converters
I've tried one of them, and they are not for converting a whole song into midi, but fine for whistle a melody into your pocket recorder and automatically converting this at home.
I can't imagine that a program is able to convert a complete song with guitar, bass, drum, synth, bongos to midi.
All in all this would be the wrong way, and never sounds the same as the original, i think.
If clubzeroy uses his 305, at least these parts are midi!
To go for a notebook is ok, but consider the price: You need a strong notebook and a PCMCIA - audio card in addition.
I knew a few guys who uses such cards (Christian Fennesz and Werner Dafeldecker) on their Apple Notebooks - i can ask them what to pay attention for, if you like...
But be aware: These things are quite expensive!
Maybe the best way for U is to buy a used cheap sampler,
the JP8000 and a mixer and rearrange your tracks for external equipment