They are essentially the same exam, but 144 has a few newer things thrown in. If you have little experience of Oracle 11g, then I would probably sit 147.
When I sat the PL/SQL exams I didn't use any guides. I just used my experience of the language over the last 16+ years, so I can't recommend a specific guide to follow. Please don's use this site to ask for or share dumps and exam guides. Exam guides are copyright material so sharing them is illegal.
Note. Brain Dumps (or their equivalents) are classed as cheating by Oracle and so anyone found to be using them will have their certification revoked. I've heard it said that people have had their certification revoked because they have been seen posting on the net asking for dumps!