I use ClueTip: http://plugins.learningjquery.com/cluetip/
If you want to see an example of it's integration, I call it like
this:
Copy script to /static/scripts
In my case:
http://trac.sahanapy.org/browser/static/scripts/S3/jquery.cluetip.js
Load it in views/web2py_ajax.html
In my case:
http://trac.sahanapy.org/browser/views/sahana_scripts_min.html
jQuery('.tooltip').cluetip({activation: 'click', sticky: true,
closePosition: 'title',closeText: '<img src="/{{=request.application}}/
static/img/cross2.png" alt="close" />',splitTitle: '|'});
Then add it to fields via the 'comment' tag:
db.table.field.comment = A(SPAN("[Help]"), _class="tooltip", _title=T
("MyTitle|MyHelpText."))
An example:
http://trac.sahanapy.org/browser/models/03_media.py
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