The only group I have at the moment is playing 4th edition. We're at level 3. I have found that online resources have been sorely lacking. If you're DMing, definitely read everything the AngryDM has written about designing encounters and such, as that advice is even more important with 4e's take on the adventuring day. Buy the Monster Vault for the tokens if nothing else (though the monsters themselves are well designed, of course), and always have a grid ready. But remember to end combat encounters before they get monotonous, easily done by scaling damage up as the battle goes on.
If you're playing and looking for more character options, try working with your DM to homebrew stuff. One of my players is using a "mechsuit" class I made, and it works well because we play a bit fast and loose with the game balance. 4e seems like its harder to homebrew for because of the careful balance they put into the design, but really it just comes down to what you and your group find fun, so if the balance is off, most players and DMs don't mind. There are some good homebrewed classes floating around the internet.
