I am a witness in a business lawsuit. The suit is in texas and the attorney's wish to deposition me in Florida. Who pays and for what?

You can't be compelled to be deposed in Florida if you live in Indiana.  Rather, plaintiff will have to depose you in Indiana unless you voluntarily agree to travel to Florida.  Thus, you can refuse to travel to Florida unless your reasonable expenses are paid.  Since this is a voluntary agreement, you can ask for whatever you want, but plaintiff will be careful to agree to pay only reasonable and necessary expenses, lest he/she/it be accused of buying your testimony (of course, this is not really an issue if the plaintiff and defendant split the costs).  If you can't reach agreement, and you are compelled to testify in Indiana, you will receive only minimal compensation, if any. BTW, if they don't want to travel to Indiana, why don't they just depose you by phone, or video conference?