As always, Apple has seeded iTunes 10.5 beta 7 for Windows and Mac along with the release of the official beta 7 firmware. Those registered in the iPhone Developer Program can now download iOS 5 beta 7 ipsws and iTunes 10.5 beta 7 from the Developers Portal.
Keep in mind that both beta firmware for iOS devices and beta iTunes software for Windows and Mac are strictly meant for developers and might break things. iTunes 10.5 beta 7 comes with iTunes Match on Mac.
So if you are indeed a registered developer, you can gain access to iTunes 10.5 beta 7 download files for Windows and Mac via the developer portal where all of the relevant files can be easily found. If you have already installed iOS 5 beta 7 on your iPhone, iPad or iPod touch you will need iTunes 10.5 beta 7 on your computer in order to sync your device with it as the old iTunes version would not sync with the devices anymore.
Download iTunes 10.5 beta 7 for Windows 64 bit [link]
Download iTunes 10.5 beta 7 for Windows 32 bit [link]
Download iTunes 10.5 beta 7 for Mac [link]