All the students who are enrolling in the external programmes,  must have to register with the related examination body to appear in the exams conducted by them. All the professional Examination body has their own official websites which can be visited to find detailed information.
The registration deadlines are mentioned below:

IMIS-

ACCA-                                

BCS-
Written Examinations 15 January for the April Sitting
15 August  for October Sitting
http://www.bcs.org.uk/
Email: bcshq@hq.bcs.org.uk

ABE-

For examinations on June- Registerion must be by the first Friday in March
For examinations on December -Register must be by the first Friday in September.

Examination Entry closing date: The December 2007 exams will take place on Monday 3rd December - Friday 7th December (inclusive).

Registration as a new student member: Friday 7th September 2007 Examination Entry closing date: Friday 5th October 2007 Entries received AFTER 5th October 2007 will incur an additional late fee of £10 per subject. The FINAL closing date for accepting entries for the December 2007 examinations is: FRIDAY 12th OCTOBER 2007.