A couple points about Full-Text searching in MySQL:
* Searches are not case sensitive
* Short words are ignored, the default minimum length is 4 characters. You can change the min and max word length with the variables ft_min_word_len and ft_max_word_len
* Words called stopwords are ignored, you can specify your own stopwords, but default words include the, have, some - see default stopwords list.
* You can disable stopwords by setting the variable ft_stopword_file to an empty string.
* Full Text searching is only supported by the MyISAM storage engine.
* If a word is present in more than 50% of the rows it will have a weight of zero. This has advantages on large datasets, but can make testing difficult on small ones.
This link might be useful to you.
http://www.petefreitag.com/item/477.cfm