Great Choice!!! Playing Open Sicilians will be a nice, new fresh thing for you. It leads to some of the most fun games in all of chess imo!
Here is some basic stuff to look into:
You can play the English Attack (6.Be3) against all 3 of Najdorf, Schevenigan, and Dragon (called Yugoslav Attack when played vs. Dragon)
However, to make the transition more smooth...maybe you want to look into the quieter, more positional 6. Be2 lines where you castle kingside as white. There is less theory.
In the Schev, Black puts his pawns on d6, e6-A very solid formation. He often tries to break with d5 or e5. Black's play also lies on the queenside with moves like b5. In the variation where white goes kingside, he follows up with mvoes like f4, going for a kingside attack with later stuff like Be3 or Qe1.
I've been a pretty dedicated Alapin player for a number of years, but lately I've been thinking I should start learning more of the open Sicilians as white.
I play the Najdorf as black, so I have some familiarity with it, but other than that all I know are a few lines in the 9. Bc4 line in the Yugoslav attack in the Dragon variation.
Can anyone offer any advise as to a good starting point in the Scheveningen? Are there any Scheviningen players out there who can let me know what the most common lines are so I can start looking at some games?
Also, is there anyone out there who was playing the Alapin who switched playing the main lines? What kinds of challenges did you face?