Yes, its not difficult if you use Calibre for the conversion. There are certainly many, many other routes for conversion.
The basic steps with Calibre are:
1. Save the FreeRead HTML file to disk. You can either display the page and Save from your browser or, with most browsers, Right-click on the PG/AU link as "Save linked content" (or whatever phrase your browser uses).
2. Install and launch Calibre (http://calibre-ebook.com/
3. Add the HTML from step #1 to Calibre's library
4. Convert to ePub (or whatever desired format) being sure to check the "Preprocess input file ..." option. The default Line-unwrap of 0.40 worked fine for my quick test just now.
The FreeRead HTML pages are simply text files with fixed line wraps wrapped in a set of <PRE> tages, given a header and footer, and then given the appropriate HTML <HEAD> and <BODY> tags. The header and footer need to be stripped and the line wraps need to be "healed" to create a decent ebook presentation. Calibre will do this if you check the "Preprocess..." option, though you may have to tweak the Line-unwrap value with some books. If you go with another conversion route (e.g. add the HTML from Step #1 to a new ePub document in a program like Sigil) you'll need to manually perform the cleanup tasks.