According to Seagate, thousands of Momentus 5400.3 drives have already shipped into the channel. The 160GB model should sell for $325, but it's IDE-only for now. Seagate won't be introducing mobile drives with perpendicular recording and a Serial ATA interface until the summer, which is a little disappointing. After all, Seagate is targeting early adopters, and early adopters are more likely to be sporting Serial ATA-equipped notebooks.
Interestingly, Seagate expects that all its new hard drive products will use perpendicular recording technology by the end of 2006. That includes not only 2.5" mobile drives, but also 3.5" desktop products.