Google (Nasdaq: GOOG) and Apple (Nasdaq: AAPL) are at it once again.

This time the argument is over advertisement sales, which will probably continue to be an integral part of sustaining Google revenue. That's especially true as the rise of smartphones makes data collection and user-specific ad techniques even more prevalent.

Google claims that Apple has changed the rules for anyone who wants to develop applications for its mobile devices, making it harder for other vendors to sell ads inside of iPhone and iPad applications. According to the Wall Street Journal: "Apple on Monday amended the rules governing the development of applications, such as games, that work with a new operating system for its iPhone and iPad devices. The language now prohibits some ad companies from collecting usage data from iPhone applications, or apps, making it harder to target ads and compete with Apple's own ad network, iAd, which is set to launch July 1."

This wouldn’t just affect Google, but also other companies that produce phones and phone operating systems, like Microsoft (Nasdaq: MSFT) and Nokia (NYSE: NOK). So far, Apple has yet to respond to Google's latest allegations -- but let’s stay tuned, and see who throws the next punch.