hey Ant1,
the ym synth does have midi (virtual over usb), to use say with your laptop and external hardware is easy, all you need is a virtual midi cable(midi yoke, maple etc...) usb conectivity, and a midi in connection to your laptop. (now there are a couple of drivers required to be on your laptop first, before any music making can be done, but they are easy to install and the manual for the ym synth gives you full instructions).
now if you dont have a midi in, there are plenty of usb midi interfaces under a hundred bucks to keep you costs down(check ebay)....if you decide to not use hardware to run the ym synth, there are also cheap alternatives aswell, me i use renoise due to the amount of midi control available, but the ym will also work with energy xt, and just about any other midi available software....a little side note...if your lacking in midi controlers to control the ym and your laptop has a synapes mouse pad check out livelab.dk's touchpad2midi i love it...but there are many virtual keyboards and such that are free and can keep your costs low...
also Wil will also mod the ym to your needs(within reason) audio connectivity, mini/micro usb instead of an 6 pin usb cable stuff like that. hell buy two put them in a case and have a ym-chip moster...check out STU-elements or any of his other work for that matter and you'll have a good idea of what can be accomplished with the ym-chip in general....cheers dk