A couple years ago I posted my treatise on running your own music for shows.
All of that info is still valid. (Except maybe the price of Go Button has gone up a bit but still cheaper and better than many other options on the market) I have decided to add one new toy in the mix.
Sometimes something might just go wrong and if you don't have a sound person who knows how your set-up works you might a bit boned. The way to get around this is to have your music player with you on stage but you might not always have a direct box to plug into and then you have wires running all akimbo.
If only someone made wireless audio cables.... oh wait.... They Do!
These items are made for guitars BUT work with any other audio devices... including ipods. You will need to nab some adapters because they use 1/4" plugs but most sound boards support that. I picked some up from Ebay for around 70$. They are Bluetooth which means you don't have to worry about weird interference. The best part is they have a low-latency which means there is no delay (that I have seen) between the time you press play and it goes. They also charge via usb so you don't have to keep buying batteries for them.
The only downside I have found thus far is they are a bit clunky in size. If you get an adapter I suggest one with a wire so your ipod is not some giant long contraption taking up space.
Now there are other bluetooth receivers for car audio auxiliary ports but they don't have a long range on them. These are made for distance while others are made for the confines of a car. These aren't the only devices made for this purpose, but they are a more affordable alternative than more high end models out there.
Feel free to do your own research but if you trust my judgement like Danny Weiser does, you might just like these.