The deal with clear and even green glass leading to skunking is all about hops. When the hop oils are subjected to light, they break down and produce the flavor and aroma described as skunky. It's not pleasant. Evidently, brown glass is able to filter the damaging light waves and prevent/minimize the skunking process. If you keep your bottled beer in the fridge or in a dark place, it's probably no big deal.
I remember the first time I tried a Pilner Urquell. I bought it at the specialty market and took it home and after the first sip almost poured it out. It was nasty and I couldn't figure out what all the fuss was about regarding this beer being the king of lagers or whatever. Well, come to find out, imported beer in green glass can sit for days and days (maybe weeks?) under the flourscent lights in the cooler. Skunk city. Your best bet for imports like this is cans or beer shipped and stored in a closed cardboard box - or - find one in a brown bottle.
The only brewery I've heard of that gets around this light issue is Miller. Evidently they use some kind of hop stabalizer that prevents the degradation by light and allows them to use clear glass bottles without this concern.
