IMO it's overvalued around $27, with a current year P/E of 13.5 & 2007 of 12.7.
If you believe the company, they can grow long term in the "high single digits". Don't know how they can know that, given all the uncertainties about their pipeline & sales of present products, & with growth next year estimated at only 6.5%, which means out years will have to be higher than that.
But even at a five year growth rate of 7.5%, PFE's PEG ratio is 1.73, about the same as its sector. Since the quality of its earnings is lower due to all the uncertainty, it's overvalued re its peers.
I've been saying it's been undervalued for months. I put it's 'real value' at somewhere between $27-28. If you are trying to use yahoo's site to see what analysts are saying, then ... well that's a problem. The company knows what it has in it's pipeline, even if they can't be 100% sure thus they can't claim it. They are saying they'll get just under 10% growth a year. That is good enough for me especially with a, just under, 4% dividend that they will increase every year too.