i would add that you should download a character sheet to help sort out the chargen process, which is a bit extensive. http://sites.google.com/site/eclipsephases/home/cabinet it's an Excel sheet by Jmobius and some other folks over at RPG.net, and it lays everything out systematically.

To echo what has already been said... 1) Read the manual. It IS big. Don't worry about the whole system gazette, that's just locations. But the rest of it is all good stuff, even if you just skim it. If you're GMing, you may want to read with some post-it notes and mark important bits you'll want to get back to in a rush. 2) If you are uncomfortable with the setting, you may want to read some more fiction. Find Schismatrix (by Bruce Sterling) and read that. There are a few changes compared to EP (namely, in Sterling's book, the culture is much older, and people still grow old and die), but overall it'll give you a strong understanding of the setting. 3) If you are uncomfortable with the mechanics and rules, don't stress. The rules are just there to help the story. Mark the important rules, try them out once or twice on your own before the game so you know more or less how they work. As GM, you are always free to modify the rules on the fly to meet the situation. Make sure you talk with your players and explain to them that you are a new GM and you are trying to run a game that is FUN, and you may break some rules on the way. So they should put away their rulebooks during play, and trust you to run the game. If you have someone else who knows the rules better than you, make a decision beforehand about whether you'd like his help in looking up rules when you need them - he can be a big help, or big trouble in the middle of a dramatic scene. 4) To start with, ignore complex things. I would probably avoid permitting asyncs (psychics) in the first group, or any hacking activity (but hackers are okay). Don't get bogged down in the details, just take it a piece at a time. 5) This whole thing is licensed under Creative Commons. That means the whole thing is free to download. Yes, do buy it, especially if you keep playing past the first game. But in the meantime, take advantage of it. Download the Gamemaster's Screen and either Mind the WMD or Glory, which are starter adventures. Those adventures are completely pre-scripted, with the characters and everything. You just need to read it before the game, and run it for your players. This will be a huge help in teaching the world and mechanics. 6) Character generation is a bit crazy. Use the excel sheet linked. Copy it over by hand if you want, or just print it out and bring it to the games. Play with the excel sheet before you actually do chargen (and expect chargen to take a session by itself). You may want to do your first game with the sample characters available, until you get a sense for the world. 7) These games are made a little easier by having a laptop on hand, to search rules, track details, look up references and so on. I would recommend having a laptop & internet connection, just for the GM. Don't permit any other laptops. Players get distracted easily, and it sinks the game. If you have any specific questions, do ask, and people will help. We were all new once :)

There are some games online, if you'd like to jump in. They move much slower than in person, but they'll give you some more background on the world and how people run it.