The four most trendy Linux developments

From desktop distros to open source virtualization, these four Linux topics are hotter than hot.

Vendors of every ilk have tripped over themselves to announce Linux-related products. We have Linux CD players, firewalls, intrusion-detectors, IP phones and routing software platforms - and the list grows daily. Applications that perform every task imaginable (and some tasks you don't want to imagine) have gushed from the open source community.