Hi thr all of u i am frm mumbai,
sorry for using such short-forms but sms has ruined my knwldg of spellings
wantd to ask some very serious doubts hope to find ans frm u guyz, have gr8 hopes frm you all;
1) I have clrd my CPT in 2009 & then hv apprd twice for ipcc but was not able to clear,
so my last attempt for ipcc was in nov 2010, DO I HAVE TO RE-REGISTER FOR IPCC to appear for my MAY 2013 exam?

Assuming that you passed CPT in June 2009, which makes 2 attempts upto Nov 2010.

No need to re-register for IPCC. There was an announcement earlier by ICAI that validity of IPCC registration is of 4 years (https://220.227.161.86/23150periodannoun2.pdf) but this was withdrawn later (https://icai.org/new_post.html?post_id=7510) There has not been any update since then. But even if we go by the withdrawn announcement, you are still in the validity of 4 years. So, as per my opinion you can appear for May 2013 exams without any further re-registration proceedings.

& if yes how to do it & when can i do it plz let me knw

2) I have also done my orientation & IT training in 2010, so do i need to do it once again?

Not required to do both of them again. 

(I hope you clear in May 2013 itself. But in any case you don't and if you are a graduate with 55% marks then there is also an option to convert to the recently launched Direct Scheme (https://220.227.161.86/27625bos-directca-form.pdf) Atleast you will be able to start your articleship and get a move on)
 

3) I am very serious for my IPCC attempt in may 2013, what changes are expected in the syllabus?

ICAI Study Material has been revised for students appearing in May 2013 exams. (https://icai.org/new_post.html?post_id=8696&c_id=342). You can see the study materials online (https://icai.org/post.html?post_id=6085). Click on a particular subject, then click on initial pages and read "A word about study material". Here you will find what are the changes made in this revised material.


4) would my CPT result be still valid? 

Valid

5) i have grewal's accounting books of 2009 for IPCC will that work or have to buy new books for the latest syllabus?

For Group 1 i think old one can work with some extra efforts. Since revised schedule vi is applicable, in company related chapters if you can understand the changes in new schedule vi. Otherwise, go for new edition. Don't know about Grewal's book, but for self study PC Tulsian is also a very good option

6) which other books can i refer plz let me knw abt that as well..
Accounts = PC Tulsian (if not taken classes earlier)

Law = Munish Bhandari (will advice to refer Ethics & Communication from study material and practice manual)

Tax = Combination of Girish Ahuja and TN Manoharan (Understanding of provisions from Ahuja and questions practice from Manoharan because in Ahuja previous year questions are not arranged chapter wise. You can also study only from TN Manoharan as well but Girish Ahuja helps in understanding the provisions in depth a bit more)

Cost FM = Don't have any personal experience of books. I read from coaching material only. But lots of people advice PC Tulsian in the forums. Check at your end.

Last but not the least, there are always study materials and practice manuals to refer.