I tried google search but I can't find good resources to learn how to use the metasploit framework.
Where would you suggest a beginner go to learn about using metasploit?
Yes, there is, it's called metasploit unleashed.
It is an official metasploit wiki with lots of information. It is structured kind of as a tutorial/course, and it gets upgraded and updated regularly. It is probably the best place to start.
More or less, everything I need I learnt from this one (however, for my needs Metasploit is more like additional tool then primary one).
In addition to the ones already mentioned, there's a fairly new book been released about metasploit by No Starch press (here). I've not got too far into it yet but it looks pretty good so far.