I essentially want one source of music coming from my pc that will be playing music inside and then have that same source sent wirelessly to my iPhone. The iPhone will be connected to a dock on the porch.
I'm looking to play the same music on my iPhone and pc at the exact same time.
I was really hoping this was something that was readily available, and I just overlooked it.
You may have overlooked a few good options.
However, I don't think you could easily synchronize what the iPhone plays with what the PC plays.
As far as I know, only Sonos has cracked the synchronized-wireless nut.
However, there may be a similar capability in Airplay. Apple must have at least considered it during design of Airplay.
Apple cracked that nut back in 2004 with something it called "AirTunes," before Sonos actually released its first ZonePlayer. So built right into iTunes for about 8 years or so you have been able to stream lossless music to multiple remote locations (via speakers plugged into an Airport Express) and have it play back perfectly "in sync" with the source computer location. And you're right, Mark, Apple eventually morphed AirTunes into AirPlay, which means you can now stream audio via AirPlay and keep it all in sync on your local Mac/PC and to any number of remote speaker destinations: Airport Expresses, Apple TVs and docks/devices that support AirPlay.
In your case, Joe, if you haven't purchased an iPhone speaker dock for the porch yet, and you get one that supports AirPlay, you're all set--you'd be able to play music locally and via that dock, in sync. Plug a $69 Airport express into a power outlet out on the porch (and connect a pair of self-powered speakers to it) and it'll show up as an AirPlay destination and likewise you'll be able to stream music to it in sync with your PC/Mac--you'll even be able to control the whole thing with your iPhone as the remote control.
What Apple has not yet enabled is an easy way to turn your iOS devices (iPhones and iPads) into "remote" speakers for AirPlay. The way many Mac users have done this is with an app called AirFoil by Rogue Amoeba:http://www.rogueamoeba.com/airfoil/mac/
There's a Windows version which I can't vouch for, but you can download it for free and demo how it works with your iPhone out on the porch and PC in the house. Might be your best option, since AirFoil supposedly supports audio streaming from any application, which should include XBMC. (Again, can't vouch for that, I use XBMC but not for music streaming.)