So you have bought an LS3020. Here are some useful posts:
Quick Newlydraw settings (Daven): viewtopic.php?f=9&t=192
Includes all the stuff you should know before you read the manual!
Getting the bed flat (bobg): viewtopic.php?f=9&t=264
Consistent cuttting and correct focusing!
Easy machine upgrades (Daven): viewtopic.php?f=2&t=235
This includes an hour counter, Power meter dial, and temperature sensors
Cleaning the optics (daven): viewtopic.php?f=9&t=234
Removal of the zozzle [sic] to clean the lens. Just be careful when you refit it (Because of here: viewtopic.php?f=2&t=331)
Height adjustment disc (PhillyDee) viewtopic.php?f=2&t=290
This fits under your LS3020
Easy engraving and cutting using CorelDraw and NewlyDraw (bobg) viewtopic.php?f=9&t=377
Models and designs (Thingiverse): http://www.thingiverse.com
Includes a lot of stuff for lasers and 3d printers! Im on there as well, just look for me!
Materials Database (PhillyDee): viewtopic.php?f=9&t=294
I compiled this list. If you find anything, give me a shout and I will add it!