I have spent the last 2 or 3 years learning about lenses. For me, some of the best advice has come from none other than Ken Rockwell. His advice is usually to invest in small, compact prime lenses rather than digital bodies. The whole idea is to get better quality equipment for less price. That is what I have essentially done and I am happy with pretty much everything that I have bought so far. He is generally quite right about equipment, and his advice can save you a lot of money in the world of cameras.
Another great resource for lens reviews is Photozone. I have bought more than a few lenses on their reccommendations because I find their reviews to be thorough and very objective. A similar site is DXO mark. And there are no shortage of reviews on the Imaging Resource. Another good one is LensTip. If you prefer the funny/creative/vulgar, then look no further than Kai Man Wong’s entertaining video lens reviews on Digital Rev TV.
If you’re like me, you get a bit overwhelmed with all the choices of lenses. Lenshero.com is one link that makes your life a bit easier to compare all of the lenses available for a certain type of camera body mount. It’s especially useful if you’d like to compare the size, weight of basic specifications of the lenses. The one down side is that Voigtlander lenses are not featured, which is a shame.
The only photography blog that I really follow is Eric Kims street photography blog. That’s it.
Other than that, Ming Thein has also written a lot about photography and takes lots of great photos. Be warned though that Ming’s writings are more like treatises or photography essays than actual blog articles (he’s also a Hasselblad / Zeiss nut). Many times I end up falling on one of Steve Huff‘s blog articles too (he’s a Leica nut though).
A popular forum that you might have already come across is dpreview.com. Loads of professional and very knowledgeable amateurs on there…