Re: Changing Description field text limit of 255 characters
regardless of what SP you are on you can't change the size fo any of the out of box default text fields.
You will need to activate and use one of the 4k text fields, place it on the form and then move the text from the 255 field into the new 4k text field. There is the ability to use Update All to move the data. Radovan has developed this and the .jar can be found in a recent thread.
If you have the leter SP's you can't change the size of the 255 text field but you have the options to create a new text field if you run out of the default ones provided.