Wireless to my audio system ?

I would like to try using my Mac and streaming it to my audio system for music stations broadcasting on line. I have not looked into stream rates nor how this stuff gets from one place to another, verses sound. My question being... What products are out there, that DOES NOT cost an arm and a leg to get started to see if I even want to go this route. Currently I am using AR pre-amp and Krell amp. Thank you for any suggestions you folks may have.
regards, Dave
Family - when you say you have Air Port on you iMac are you referring to the Airport software that is installed on all Macs or do you mean you have an Airport Express wireless access point, which is an external device to which you stream data? And what do you mean by 'the Air Port comm.'?
I'm tech-challenged but was able to set up a system that I'm extremely happy with. Bought an Apple Time Capsule with 1T of memory for storage/router on which I've saved my 700 cd library using iTunes in lossless format. TC streams music to a Zardoz (French modified Airport Express) which I have wired into my pre downstairs in my listening room. Bought an iPod Touch to use as a remote. Still have my Arcam FMJ 27T cd player in my system, but not sure why. Once you get set up, you'll never want to go back to manually feeding your cd player!
2nd the AE or AppleTV (ATV!)

you do NOT need a wireless router when using MAC. I run my AE as a 'client', which is a dead end connection.

I use my iPod Touch as 'remote'. You can even listen to internet radio, though I'm still trying to figure out how to select a URL for the station....I'm currently limited to those stations which are listed in iTunes.

Be careful in DAC selection and try first, if possible. My AE simply puts out something which my CA840c, used as DAC, does not like. I went back to the less good analogue connection.

Difficulty? 4 on a 10 point scale. Running the Airport Utility is easy and all I do to turn it on is enable my computers airport. Connects right up.