Assuming you are wanting to play 3.5 version of D&D (That is what you placed in your thread) it will depend on where you left off on D&D.
1. Wizards still has many support docs and adventures in it's online archive (you will have to sort it through all the 4e crap from last year). They don't "officially" support it anymore.
2. Familiarize with the rules in the PHB which includes all the race, spell, class, and combat information. That will be the brunt of the changes from earlier editions. Though I must confess I really never played 2e much as 1e and 3e. Finding a 3.5 PHB maybe a little tricky unless you buy off someone else. The DMG and Monster manual would be good.
3. As an Alternative you can play Pathfinder from Pazio which is "D&D 3.75". Rules are free.
Let me know if you need "more".