Can you mod gta ballad of gay tony on ps3?

The Ballad of Gay Tony is a Microsoft exclusive for the Xbox 360 only. Whether it will ever become available for the PS3 is unknown at this time.

NEWS UPDATE:

In case this is of interest to you, I have just read an item that announces Episodes from Liberty City, which includes Gay Tony, (previously an Xbox 360 exclusive) is to be apparently available for PS3 and PC on 30th March this year.