USPuzzles, Round 2!

My other introduction to recreational puzzling came from a series of fun (now possibly out of print) Usborne Puzzle Adventure books.  The puzzle I remember most strongly is a coded message.  I needed quite a bit of parental help at the time, but I still remember the tricks we used to get started.  I’ve tried to code a similarly solvable message for this puzzle.

I am curious to know how other people try to solve things like this, so if you make an attempt, please share your successes and frustrations in the comments.  Without further ado, here’s the coded message:

O FGZT ZIQZ GFT GY ZIT YXFFN ZIOFUL QWGXZ EGRTL (TLHTEOQSSN Q LODHST KTHSQETDTFZ EOHITK SOAT ZIOL GFT) OL ZIQZ GYZTF ZIT SGFUTK ZITN QKT ZIT TQLOTK ZG UTZ KOUIZ ZITN WTEGDT.  ZIT STFUZI OFEKTQLTL EGFZTBZ QFR ZIT OFEORTFET GY EGDDGF VGKRL QFR STZZTKL SOAT “ZIT” QFR “T”. LG O QRRTR Q ZIOKR LTFZTFET YGK ZIT LQAT GY TBQDHST QFR DTZQ-EGDDTFZQKN.

The punctuation and spacing are correct, but each letter in the code stands for a different letter.  Yes, it’s a bit long, but there’s a reason.  Good luck and happy puzzling!

EDIT! I have been alerted that I misspelled a word! ENHITK (it was inside the parentheses) should be EOHITK.  This has been corrected above.  Very sorry, and credit to Alex Oprea for the correction