LimitNone LLC, a tiny start-up that builds a tool for migrating customers off Microsoft’s Outlook email software and on to Google’s Gmail as filed a trade secrets lawsuit against Google.

The suit claims that Google had initially promoted the migrating tool. Google then copied the idea and went into competition with LimitNone.

LimitNone is seeking reimbursement from Google of actual damages, attorney’s fees and punitive damages. LimitNone’s case details the company’s meetings starting in March 2007 with Google to build a tool it named, “gMove.” This tool was used to move the e-mail, address books and calendars of corporate customers from Microsoft’s Outlook to Gmail. David Rammelt, lead plaintiff’s attorney said that LimitNone had been told by Google that 50 million subscribers was “just too big to come from someone else.” A simple calculation of the lost revenue for LimitNone “very quickly gets you up to about $950 million.”

The case hangs on the fact that LimitNone claims it entered into a confidentiality deal with Google to share trade secrets of its e-mail migration tool with the search giant’s engineers, sales people and key Google Apps customers.

The meat of the case is the fact that Google introduced a free, competing e-mail migration tool earlier this year called “Google Email Uploader.” The lawsuit alleges that this tool is “almost identical” to gMove and that “both operate under a similar conceptual design.”

Following news that Google had decided to compete with it instead of continues its partnership, LimitNone shifted its business to focus on the emerging market for business software designed to run on the Apple’s iPhone.