Good Spots to Find PvP Action (Invasions, duels, etc.)

Now I'm not too well versed in the PvP world of Dark Souls, but I'm looking to start my adventure into it! What areas can I expect to find myself any kind of PvP action, whether it be me getting summoned into someone's world to fight people, or through being invaded myself or using something to invade!
I'm looking to be a Dark Moon, so if I could be present with some good spots to go invade as a Dark Moon, that would be much appreciated! But any PvP action will work for me.
Please be sure to mention any level ranges I should shoot for or hit. I know the typical max level determined by the forums is level 125 for PvP, correct? If I hit that, where could I go for fights?
Thanks a lot guys! Help is always appreciated!

Hello fellow Darkmoon. Please tell me that your avatar is not Gwyndolin. Anyway, if you are aiming for SL 125 (the forum's FC is 120) you should go to the Burg, Kiln or moonpit if you want some duels. Be wary that if you invade you may encounter the despicable gankers, so you could get good 3vs1 practice while searching for duels. For invading the pitiful guilty questers you can be any SL and try to invade any area you like, because Darkmoons can invade all the levels down (even SL 1 pfffff). I like to invade in Painted World and sometimes kill the gankers of the forest and dark Anor Londo. Remember to have fun and the guilty always pay the price.

Indeed it is, bwahaha! Incredibly feminine version, but still a rendition of my great lord I do enjoy! Anyhow, thank you very much for the contribution, brother. Those all sound like good areas to go, although I am not familiar with what the "moonpit" is. Where can I locate that?

Ill try Anor Londo/Painted World, since they are nice and close to one another. Anor Londo is huge, does it matter where used my orb in Anor Londo or is that irrelevant?

Once again, thank you, brother! Those sinners days will be numbered with my addition to the Dark Moon Blades

Damn I always see him as a man so it's a bit disturbing when they say or even draw him as a girl!!!

Moonpit is the code name for the pond that has a flower in the moonlight butterfly garden. It's just before the first stone knight.

Invading in Anor Londo varies per Area. That I know of:

-If you invade at the first bridge you'll spawn there, it's a gankers hang out watchout.
-If you invade at Darkmoon Tomb you spawn at the main gates where the 2 giant sentries stand.
-If you invade at the fog gate of O&S you spawn right there at the stairs.
-If you invade at Solaire's bonfire you'll spawn in the hall outside bonfire.

Also you could equip Gwyndolin's ring and invade the gankers of Dark Anor Londo.

yesterday was doing duels in Burg and was pretty well an occasional WoTG Spammer and a group of Gankers that were like 3 idiots! but I was pretty well!

I just see it as an incredibly feminine Gwyndolin, but still a male nevertheless due to lack of female only attributes xD Anyway, thank you for the helpful info. This'll all help me better plan my attacks against the sinners of this world (and satisfy my PvP desires!)