You can add marks in the left side column of all the enchantment lists to show the enchantments you can make. Don't worry, you won't have to write down the enchantments — an addon will do all the hard work for you. It will figure out the enchantments you have and generate a link for your web browser. You can then bookmark it for your own reference or use it in e.g. a guild forum.
First, download and install the addon Read Enchantments. Addons for World of Warcraft are usually placed in the following folder:
<World of Warcraft Installation Folder>\Interface\AddOns\Unzip the archive into that folder. You should then have a new folder called ChordReadEnch
with four files in it.
Now start World of Warcraft and log in. (When you enter the character selection screen, optionally click the AddOns button in the bottom left corner. In the screen that appears, make sure the Read Enchantments addon is enabled.)
Log in with the character that can enchant and open the enchantments window. A new button called URL should be available in the top, just next to the search box.
Click it now to open a dialog box containing the link.
Note: If the button is not present (because of clashing with another addon or whatever the reason may be) you can also activate it with a slash command. Just make sure the enchantments window is open and then type either /cre or /chordreadench.
As the dialog box suggests, you should mark the entire link with Ctrl+A and copy it to the clipboard buffer with Ctrl+C. Exit the game (or task switch out of it) and then paste it into your favorite web browser — either by right-clicking the address field and selecting Paste, or by hitting Ctrl+V.
The weapon enchantments page should appear with marks in the left side column. All the sections should have these marks. Your character name has also been conveniently added to the page.
You can now bookmark any page for your reference, place the link in guild forums, etc. Remember to generate a new link in the game whenever you have learned a new enchantment.
If you find any bugs in the addon (or glitches regarding what marks are shown) please send me an e-mail about it! =)