If you are a fan of the 2d20 system, like punching Nazis, and the Cthulhu Mythos is your vibe; Acthung! Cthulhu 2d20 Quickstarter is definitely worth taking a look. And with a free price-tag, how could you say no? I will say that there were a few elements I felt were missing in the first section on game mechanics; I saw things in the adventure module that made we want to know more about how things worked (you really need to dig into the NPCs and Pregen PCs in the adventure to find them) but was not discussed in the rules-section.
Most of us are uncertain when we are called upon or take up the mantle of Gamemastering for the first time. Naturally we turn to the internet to find tips and tricks on how to prepare. These are my oft-overlooked suggestions for new and first time GMs.