Here is a great tip that can save you hours of work. Sometimes you have messed up characters in your database - wrong character encodings - or you want to strip out some text in a certain table's field. In phpMyAdmin, open up the SQL dialog and use the following code (change tablename and tablefield to your name and field values):

UPDATE tablename SET tablefield = replace(tablefield, "findstring", "replacestring");

You can also tack on a WHERE statement, if you like.

I found this tip on Brian Zimmer's website.

Tested on MySQL5, PHP5 and phpMyAdmin 2.11.4.