obtaining currency exchange rate values for different coins via apis ive been trying to work out what the best way of obtaining the exchange rate of a bitcoin or any other digital currency is via online resources for a website I want to build.

I've seen this question/answer here; Displaying price in BTC based on USD exchange rate

So sure thats easy but what about other coins against the dollar or against bitcoins.  Am I going to have to obtain all this info from different sources?
If you are not actually trading, you can pull the price from multiple exchanges and show an average, since there is no such thing as fixed price for the exchange, preev.com is a nice converter that shows average of 4 sources which you can modify from the settings menu, it should give you an idea.