My Walkthrough for fighting creepers:
You will Need:
A sword, preferably Iron or Diamond
A large open area.
The trick to killing creepers is timing. Since they can 'see' you through obstacles, stuff like getting them caught on a corner and wailing away, like with Skeletons or Zombies, doesn't work.
First, get acquainted with the 'range' of the sword on animals. Since Minecraft handles blocks and animals with a different range of effectiveness, you have to find out where your comfort zone is. To test this, find your average unsuspecting pig, and slowly move towards him, finding out just how far your sword can go. I find that the max range for me is a block and a half away, though I haven't conclusively tested this.
Now that you have range, you need a place where you can not only circle-strafe, but back away beforehand without running into obstacles. Beaches work well, since Sand is easy to clear and a duel on the beach is always awesome. If you can't find that place, then make sure you get some idea for the terrain so you don't back yourself into a wall you can't jump.
After that, it's simple. Hit the creeper at max range, then back away from him. A second or two seconds after he STOPS HISSING [very important], repeat the process.
This is good for until you get the bow, or get some pressure plates, red ore and TNT. Then again, there's pit traps, burning traps, water holes, hitting him when he's on a ledge below you...
Final note: Though they can 'see' past corners, making a corner trap impossible, they can't see diagonally or vertically. So if you're above one, look down and hack away.
