If you need to see what you are actually changing in your theme.php file you can easily do it by copying the code you will be modifying and pasting it into a completely blank page in any html editor such as dreamweaver and viewing it in design mode. This makes modifying the template easier for some people. As an example I was just making changes to the sort order links and below you can see the output from selecting the code for just below
// HTML template for title row of the thumbnail view (album title + sort options)
in theme.php pasting it then changing to design view in dreamweaver. Be sure to paste it while in code view or paste it into a text editor save as .html and open in your html editor.