Data Rescue 3 (trial lets you scan the HDD and see, if data is recoverable, but to actually recover files, you need to buy the full version for 99 USD) or FileSalvage (trial lets you scan the HDD and see, if data is recoverable, but to actually recover files, you need to buy the full version for 89.95 USD). DiskDrill - lets you recover data from HFS/HFS+, FAT, NTFS & other file systems right on your Mac., for free.
Also know, that you should immediately stop any writing processes to the actual HDD. If it is the same HDD as the one your operating system (OS) resides on, it is better to use an external HDD with Mac OS X on to boot from and install Data Rescue or FileSalvage onto to scan the HDD from which the data has been accidentally deleted.
I did the EXACT same thing! I can't afford to pay $100 for a license, but i can't use disk drill because it doesn't support OS X 10.4! Lotso, did you find any solution to your problem? I'm freakin out!
If you do not want to spend any penny for your recover then disk drill is good choice but no 100% data recovery guarantee. There are some good features in paid recovery programs which are lacking in disk drill like recover data with original file name and recovery of data upto 4 TB.