I live in McAllen TX, about 60 miles west of SPI. (Moved here from WI 2 years ago). Here is a link with some names and phone numbers of charters out of SPI. http://www.sopadre.com/fishing.asp
I’ve been on the Osprey before, took the 8 hour trip. Pretty reasonable (about $60 if I remember correctly), includes tackle, bait and lunch. Boat goes out 15 miles or so (2 hours out – 2 hours back. Only 4 hours fishing. Make sure you have your sea legs, I spent most of the time chumming!. About 40 people/boat, saw lots of fish caught, including a 6′ shark.
If you need any other info, let me know and I can get it for you.
Ryan