The cartoons are canon right?
Lucasfilm claims that every work of SW fiction is canonical, but Lucas feels free to contradict them in new cinematic works whenever he chooses. Which is pretty much true of any canon; follow any long-running series, even in a single medium, and you'll see it contradict itself eventually, whether by accident or by intent.
Keep in mind that there are two animated series.
Star Wars: Clone Wars was a 2D animated series (like traditional cel animation, although even "traditional" animation is mostly made on computers these days) with very short episodes (mostly 3-5 minutes, sometimes up to 12), telling a variety of stories set during the Clone Wars and culminating in a depiction of the events leading into
Return of the Sith.
Star Wars: The Clone Wars is the current series of half-hour, 3D-animated episodes, and although it uses the same characters and setting as the previous series, I don't think it's entirely consistent with it. SW:CW was considered canonical at the time, but newer canon supplants it in the event of contradiction.
So this show is canonical until Lucas says otherwise, just like everything else in SW.
Uneven. The 2D animated series was pretty good for what it was, a pure action show. The 3D series started out fairly weak but has gotten progressively more solid, smart, and engaging.
When do these take place compared to the movies, etc? Like is this all stuff that happens right after episode 3?
The Clone Wars began at the end of Episode II and concluded in Episode III with the fall of the Republic and the founding of the Empire. Naturally, both Clone Wars series take place in the 3-year interval between
Attack of the Clones and
Return of the Sith.