keepitcoming,
This is the way I understand it:
When we bring a korban to Hashem, we should bring an unblemished, beautiful animal – the best that we have. Now that we have no Beis Hamikdash, we follow the words of the prophet Hoshea, “let our lips substitute for bulls.” So our prayers, our words of praise, requests, and thanksgiving, are like korbonos to Hashem. In that light, the words of tehillim, pure and beautiful, represent some of the choicest offerings that we can bring.