I just bought a set of Sharper Image wireless speakers at Bed Bath & Beyond for $99 minus the 20% coupon you can get everywhere (Linens and things has them too). I hooked them up to my AppleTV, and was surprised at how well these cheapies work! Plus, they look nice too. I figured, right now, I've spent so much on the Hot Tub, Patio, Screen, electric........plus the Holidays, I'd try out the cheapies before dropping another bundle. I don't think that with jets on I am that concerned about sound quality, but I was surprised at how well these did. You can plug the receiver into a headphone jack or audio out. That way you are not limited to just use with your ipod also. I am using it with my home theater (but right now I have a 14 foot Christmas Tree blocking the view of my plasma TV from the spa). These are wireless, and run on 6 C batteries per speaker.
I just hooked it up yesterday, so I can't attest to anything long term. Good Luck!