[CentOS] Extract text from Microsoft PowerPoint files

Hello CentOS people,

I'm wondering if there are command tools like antiword and docx2txt for 
Microsoft PowerPoint files (.ppt and .pptx).  The idea is to extract 
text from PowerPoint files.  Sorry this isn't exactly about CentOS, but 
I'd really like it if Yum has something.  I tried xlhtml, but it hasn't 
been updated in a while and isn't exactly wanting to work on CentOS 5.

Thank you,