Alright guys, today I am going to be telling you step by step how to install optifine mod for minecraft 1.6, 1.7, or any future update. But note: optifine must be released to download it, and you will of at least had to open the minecraft version once in the past for the version of optifine you are downloading. On the link provided you can download optifine, and if the version for the update isn't ready they'll tell you the percent. Enjoy!
Download Optifine Here:
http://www.minecraftforum.net/topic/249637-164-optifine-hd-c8-fps-boost-hd-textures-aa-af-and-much-more/

Step 1. Click the link or find the site yourself.
Step 2. Once on the site scroll down to find the download, it should be located under the golden donate button that looks like this.

Step 3. Click the download for the optifine you want (Ultra is recommended).
Step 4.Once you click on download it should pop up an Adf.ly ad, just let it go and skip and ad in the top right corner.
Step 5.Now you should of been redirected to a page with only the download, download that.
Step 6 (only some). If it says it can harm your computer, it won't, and just click 'keep'.
Step 7. You want to get the download of optifine you just got, and drag and drop it onto your desktop.
Step 8. On your desktop, right click the download icon you just put. Locate where it says open with >, and open with Java(TM) Platform SE binary. Click it if you haven't't already.
Step 9. Once it pops up the little window where it says Install or Cancel, click Install.
Step 10. Start your minecraft launcher and get to the sign-in page.
Step 11. Make sure you are signed in on the left and go into 'Profile' on the right.
Step 12. In 'Profiles' select 'Optifine' and then hit play.

You now have Optifine. I hope I have helped. Enjoy!
NOTE: Optifine for 1.7 is currently 100% done! It's ready!