Hi Karnik, how are you?
If i am not wrong, you are the same karnik gulati from delhi who was taking mafa classes from rajiv singh sir..humm.
well, my dear frnd the answer to your query is so simple as you would be able to appear in may 2010 attempt of CA final if your articleship gets completed on 28th april becos under old scheme the one has to be in last twelve month training period on the first day of the month in which he has to appear in exams i.e; may/nov.
but under new scheme since your articleship would get completed before the first day of the month in which you are appearing so you will not find any difficulty as per my opinion.
so dont worry and prepare well.
karan.