The following information is for several of our older high school girls that want to play both high school softball and Little League softball. From what I read, you will be able to participate in Little League, after your team looses sectionals and your high school coach approves it.
Here is the website, so you can review the information...
IHSAA Softball Rules
Here is the dates for IHSAA...
IHSAA Softball Schedule 2004
If there is any other question or concern please talk with your high school coach. IHSAA rules supersede Little League rules.
As far as middle school goes, I don't believe IPS has any documentation on playing for both teams. I would suggest you ask your middle school coach to make sure it is O.K.