It originally aired in Japan from 2008 to 2009. The first episode aired on Toonami this past weekend though interestingly it’s been available on Netflix for some time. The series is 51 Episodes long (22 episodes more than FMA:B) so you’ll get a full year of Soul Eater assuming the ratings are good and they don’t re-air reruns (Aside from Bleach and FMA:B they’ve been doing a great job not doing reruns).
If you have Netflix obviously you have a choice as to how you want to watch it. You can either watch an episode a week or do what I do and just watch the whole series in full. I watched all of Samurai 7 on Netflix before it finished airing on Toonami and still watched it when it aired. Funimation Tweeted over the weekend on Toonami’s twitter page. I can only hope this is a tease for more shows coming to the US. That would mean new Anime coming to Netflix, which it badly needs.
For those interested in watching both version are Dubbed but the Netflix version is uncut. I just finished rewatching the first Episode on Netflix and noticed a few extra scenes I didn’t see in the aired version. Nothing noteworthy but the aired version was shortened to fit in commercials.