Here are my favorite keyword tools to use when starting any online campaign. There are also some great paid tools, but I will cover them in a later post. For now, enjoy these:

Free Keyword Tools

Google Keyword Tool
The Google keyword tool is great because it is free. It shows you historical trends on selected keywords over the last 12 months. It also has the ability to analyze a particular site or page and tell you what the best keyword combination would be. You can also get estimated costs per click when using Adwords.

Overture Keyword Selector Tool
This is the original keyword research tool. It does provide lots of valuable information and variations on the term you provide, however it is so widely used that it makes it hard to use as an advantage over your competition.

Digital Point Keyword Tool
This tool uses both Overture data as well as free Wordtracker data and compares them side by side for you.

Microsoft Labs Keyword Forecast Tool
This tool displays trends on a particular keyword as well as shows you demographics on who is searching for these words.

Keyword Map
An interesting tool to use to see how keywords are related

SEO Company Keyword Tool
A simple interface to show you search queries volume and related information

SEO Book Keyword Suggestion Tool
Quite possibly the most comprehensive free tool available. Try it out and you will see!

Do you have any other suggestions for free keyword tools? If so, please leave your favorites in a comment