Louie Mantia is leaving Apple, where he served as a visual interface designer for the company’s iTunes Design team, an announcement was made yesterday on Twitter. He is leaving for Square, a San Francisco mobile payment startup founded by Twitter co-founder Jack Dorsey. Square, as you recall, is behind an iPhone app and the accompanying dongle which turns the handset into a cool mobile payment terminal.

Apple loves it and we’re sure Mantia will appreciate it, too, when getting paid for freelance work. The iTunes Design team is “specifically looking for visual designers”, Mantia wrote on Twitter, advising candidates interested in filling his shoes to link him to their portfolio:

If you’re not familiar with the name, here’s a little backgrounder to get you up to speed…

Louie Mantia designed one of the best Apple icons, among other things, including the controversial iTunes 10 icon. He joined Apple at a really young age, while he was just 21 and without a college degree. “I contacted them about a job and we scheduled interviews. I think this is how the hiring process works at most places”, he explained. He actually came via Iconfactory and prior to that Mantia had already made a name for himself in the Mac icon and iPhone development communities. Played Tap Tap Revenge, an addictive iPhone music game from Tapulous? Mantia was on the original development team. Obama ’08 app? Mantia did the user interface for that. The list goes on and on and on so make sure you check out his portfolio site, it’s pretty hot. On a final note, Mantia is also a strong believer in free (or at least pretty inexpensive) WiFi, per this tweet: