for what it's worth, I've never found any problems with Google indexing PHP pages on sites which I've had any dealings with.
There may be a problem with completely dynamic content, such as /showjobdetails.php?id=1234
Where you have potentially thousands of different jobs, identified by unique id's.
If the details for an individual job are unlikely to change very frequently, you may find it better for search engines, and faster for your visitors, to publish these files periodically (every day, or every 6 hours or whatever) as simple html.
On the other hand, if the details DO change frequently, then do you even want google to store them?