First, double check that the correct data is in your RSS feed. You can reply to this post with your RSS feed if you want more help with that specifically. Make sure this is the feed to your blog and not a 3rd party service such as feedBurner. If your using Feedburner, go to
www.feedburner.com for help.
Also make sure you didn't uncheck the appropriate setting that gives your summary that nice look. Go to PowerPress Settings > iTunes tab, make sure the option "iTunes Episode Summary" [] "Optimize iTunes Summary" is checked. You may need to click the link "Show Advanced iTunes Settings" if you do not see the "iTunes Episode Summary" option. Also, read the note below this field as the nice look of the show notes doesn't look that good in the new iTunes web pages.
Last, iTunes can change how they display the data when ever they want, so keep that in mind.