Calculate it yourself. It is available on many sites. But it isn't always up to date. When a company reports earnings, there is almost always a few days (or longer) before the data is up to date. (ORCL is a good example.) If you calculate your own data you can always update what you want in a matter of minutes.
Second, sites often they don't agree with each other. So if you are going to get your data from a site, you need to use the same one all the time.
I use www.finviz.com.
It's free and lets you export the entire stock market's fundamentals with the click of a button.
P/E is usually available on stock sites.
It may not be in a brief listing of daily activity or newspaper listing but you can look stocks up on sites lite Yahoo Finance and the P/E is one piece of information that is listed:
Here is Oracle stock, P/E listed in right column
http://finance.yahoo.com/q?s=ORCL
Do I have to calculate ratios such as the P/E indicator myself or is there a up-to-date information such as a website or tables I can go through?