This is possibly the biggest news this year so far, along with the return of classic DnD products. The Internet Archive has uploaded a pretty much complete collection of scanned Dragon magazines. The scans are available for reading online, as well as downloading in a variety of formats. As if that wasn't enough, the Archive also appears to have a collection of the Polyhedron zine, Dragon's little brother for the RPGA network.
Both of these collections are treasure mines, considering that Dragon was the foremost magazine for roleplaying games for a very long time and each issue contains a wealth of information for DnD and other roleplaying games. I started reading Dragon well into the AD&D era, but I bet it will be fascinating to see how the game evolved from the basic set to 3rd edition through the pages of the magazine.
The actual legality of both collections is, shall we say a grey area. This means they may not be around for long if Wizards decides to challenge the matter. My suggestion would be to get them while you can cause they might not be there tomorrow.