Okay so lets get started. There are many steps to this but it shouldn't be to difficult, the hardest part is port forwarding anyway.
Step 1) Okay so the first step is to make a new folder on your desktop and name it whatever you like( I named mine Minecraft server).

Step 2) You are going to have to download the Bukkit jar file from here: [ Register or Signin to view external links. ] (when you get there click the button that says beta build|1.6.2-R0.1|14.6mb) [ Register or Signin to view external links. ] )

Step 3) Once the file is done downloading drag it into your folder you made on your desktop and rename the file to craftbukkit (do not run this file yet).

Step 4) Next we will need to download BukkitGUI from here: [ Register or Signin to view external links. ] Click this one: [ Register or Signin to view external links. ]

Step 5) After that finishes downloading drag it into your new folder and then run it

Step 6) After it starts up go to the "SuperStart" tab. [ Register or Signin to view external links. ]

Step 7) For the next step we will need to know what Java version you are running and what bit operating system you are on (if you already know this skip to step 8). First to find out what java version you are running, run minecraft, then open taskmanager ( right click the bar at the bottom of the screen and then click start taskmanager [ Register or Signin to view external links. ] , then look for a task called javaw.exe and right click it and then click open file location. It should bring up a window and you will want to look at the top address bar and see what version of Java you have [ Register or Signin to view external links. ] as you can see in the red box I am running Jre7. Next you need to find out what operating system you have so go to Start> Control panel> System> then look here [ Register or Signin to view external links. ] so I have Jre7x64

Step 8) Once you have figured out your java version select it from this list [ Register or Signin to view external links. ]

Step 9)Click on this button [ Register or Signin to view external links. ] and then locate your craftbukkit.jar file and click on it.

Step 10) Click launch server [ Register or Signin to view external links. ]

Step 11) Let it run until it says done and then type stop in the chat bar [ Register or Signin to view external links. ]

Step 12) The next part of the tutorial will be port forwarding and we will start by making your computers ipv4 address static to do this you will need to download this [ Register or Signin to view external links. ] click here
[ Register or Signin to view external links. ]

Step 13) Run the setup file for static ip and while it is installing it will give you 3 offers for some stupid freeware and toolbar stuff just decline those.

Step 14) When it finishes installing run the program and then click make it static, a window will pop-up click apply and then apply changes.

Step 15) Write down or remember what your new ipv4 address is it will be right here [ Register or Signin to view external links. ]

Step 16) The next part is different for everyone so you will have to go to [ Register or Signin to view external links. ] find your router and then click Minecraft server and then follow the guide on how to port foward for your router

Step 17) Everything should be ready to go, run your server with BukkitGUI and then start inviting your friends to join( Give them your external ip address, which you can find out at [ Register or Signin to view external links. ] )