Below are the links that offer the best selected joomla 1.5 free templates that are widely used and most downloaded. No Membership needed, you just need to click the download button.
1. http://www.rockettheme.com/joomla-downloads/113-free
2. http://www.joomlart.com/forums/downloads.php?do=cat&id=145
3. http://www.joomspirit.com/free-templates.html
4. http://www.templateplazza.com/free-joomla-1.5-templates/
5. http://www.joomlapraise.com/free-joomla-templates/demi-joomla-template.php

6. http://www.joomlapraise.com/joomla/templates/free/dailypraise-redux.php
7. http://www.yagendoo.com/en/joomla/joomla-templates/city-sky.html
8. http://www.bestofjoomla.com/component/option,com_bestoftemplate/task,detail/Itemid,46/id,2554/
9. http://www.bestofjoomla.com/component/option,com_bestoftemplate/task,detail/Itemid,46/id,2720/
10. http://www.themza.com/joomla1.5/

I already tried adding lightbox 2.04 in a blogger and it works perfect to my blog. Now i tried another type of lightbox and it is called multibox created by phatfusion and the latest version now is multibox version 1.3.1. This lightbox supports images, flash, video, mp3s, html.