THERE IS AN INTERESTING new site that opened up called Need An Eitzah. It is similar to the stack exchange site Mi Yodeya with the exception that it allows for opinions as well. I think it’s a great site. Here is a quick bit of Halachic information that I posted as an answer there today:
The Gemara says that someone who gazes upon the Kohanim in the Beis HaMikdash while they are standing on their platform and blessing the Jewish People; such a person’s vision will fade.
כל המסתכל בג' דברים עיניו כהות... ובכהנים... בזמן שבהמ"ק קיים שהיו עומדין על דוכנן ומברכין את ישראל בשם המפורש.
Anyone who gazes at three things; his eyes become weak… and at the Kohanim… when the Beis HaMikdash was standing, when they would stand on their platform and bless Israel with the explicit name. 
It is clear from the Gemara that the only real issue is when the Beis HaMikdash was around. However, Tosafos say that even nowadays there is an issue with staring as it can lead one to lose focus from the blessing.
Based on this, the Mishna Berura writes that according to the letter of the law one is only not allowed to gaze intently, in a way that will cause one to lose focus from the blessing, but looking a little bit is okay. However, he ends off that the custom in his times was not to look at all, as a remembrance to the times of the Beis HaMikdash. This explains the prevalent custom not to look in the direction of the Kohanim at all, even though they are customarily covered by their prayer shawls anyway. It is just a remembrance, it is not Halacha.