Parsing PDF files

Wondering if anyone has tried to parse out a table of information from a PDF file? Is it a matter of opening the file, looping through its contents line-by-line looking for tags that demarcate table cell boundaries and extracting the relevant cell values? I figured if Google can index PDF content it must be possible to pull the content out something like one would an HTML file. Mostly wondering how much work might be involved and if there are any tricks that I should be aware of before I begin... Regards, Paul