Text as in a part of the image, in Flash, or text overlay in XHTML, jQuery, and CSS?
If you want it as a part of the image and you don't have Photoshop, download Gimp. It's basically open source Photoshop, Illustrator, etc...and sometimes better.
http://www.gimp.org/
If you're talking about XHTML text overlay, then I would suggest checking out jQuery. Just do a Google search for what you want and add jQuery and you'll find a script someone else already wrote. You just have to implement/modify it. A pain if you don't know XHTML or CSS.
With Flash, you can download
http://www.photo-flash-maker.com/ - it's really easy to use with a ton of templates. It's not free, but worth the marginal amount they charge. They have some cool 3D effects.