Serena Software on Monday will tout plans to offer several of its products via SaaS.The first product to be offered via this format will be Serena Mariner, the company’s project and portfolio management (PPM) tool. Mariner offers visibility into project status and metrics to ensure the right persons are on a project at the right time, the company said.Users can try the SaaS version free and buy it online. Pricing will be half the price of alternative PPM offerings for the first six months, Serena said. Also planned for a SaaS implementation are solutions for Business Mashups and the agile space. Software Development