Visa Inc. has reportedly made an “unspecified investment” in Square. The investment was made in exchange for a seat on Square’s board, according to Reuters.

Recently, Apple started selling Square’s highly publicized iPhone credit card reader (it’s available for just $9.95). Apple even showcased Square at its iPad 2 event.

Now, Visa Inc. – the global payments technology company – has thrown some cash behind Square, and is sitting in on the company’s board meetings.¬†Interestingly, Square was created by¬†Jack Dorsey – one of Twitter’s cofounders. Back in March, Dorsey returned to Twitter, assuming the role of “executive chairman” while continuing to oversee things at Square.

Do any of you guys use Square’s iPhone credit card reader? Let us know your thoughts on the device in the comments.