How to display the contents of a custom profile text-field inside a tooltip?

[Grover]

Hi,

I have created a custom user profile field. It's a multiple line textfield. A user fills this in, for example:

---------------------------------------
His this is line1 of the text I fill in
His this is line2 of the text I fill in
His this is line3 of the text I fill in
His this is line4 of the text I fill in
His this is line5 of the text I fill in
His this is line6 of the text I fill in

His this is line8 of the text I fill in
His this is line9 of the text I fill in
His this is line10 of the text I fill in
---------------------------------------

What I would like to have in the postbit (beneath the username) is this:

- VB3 checks if this field is filled in our not

---- If it's not then it displayes nothing.
---- If it IS then it displays an image (say 'show_field.gif') and when you hover over this image, a tooltip appears with the contents of the field above.

How can I achieve this?