Lawrence Jacobson, who worked at RealNetworks for three years, resigned, effective immediately to pursue other opportunities and spend more time with his family, the company said in a statement.

The firm reported that legal costs for the Microsoft fight were $2.3m in the first quarter, compared to $1.6m in the fourth quarter, but lower than the $3m the company predicted in January when it reported its full-year results.

Net loss for the quarter ended March 31 was $10.4m, compared to a loss of $2.8m a year ago. Excluding legal and other charges, the pro forma net loss was $3.2m compared to a fourth-quarter loss of $3.8m. For the first quarter, revenue was up 29% at $60.4m.

RealNetworks is now involved in a war of words with rival digital music outlet Apple Computer Inc. Apple CEO Steve Jobs was quoted yesterday as saying RealNetworks’ business model, providing subscription services, is not succeeding.

RealNetworks CEO Rob Glaser said Jobs’ comments were ridiculously humorous and pointed to RealNetworks’ 55% growth in music revenue as evidence that the model works, according to the Reuters news service.

Glaser recently proposed a strategic alliance with Apple in an email to Jobs, threatening an alternate alliance with Microsoft, which caused embarrassment when Apple publicly declined the offer by leaking the email to the New York Times.

The email suggested that RealNetwork was seeing very interesting opportunities to license Microsoft’s Windows Media formats, which some said will hurt RealNetworks’ case that Microsoft is behaving anti-competitively.

This article is based on material originally published by ComputerWire