Please Help: income tax

I am confident u will help me out to clear following queries and in filing of my e-return for income tax for fy 2010-11. 1) i have short term gain from shares, but i have not paid any tax on this. however, compulsory deductions like st, stt etc. have been charged/deducted by broker. 2) how to club it with salary income. though i have been trading in shares for last 3-5 years, but never reflected incomce on this a/c in my earlier returns, may be due ignorance of rule position. 3) is income earned by nri through consultancy services taxable. I believe it is not. if not,is it necessary to file return. 4) if part income in a particular financial year earned in india is less than say rs.1.50 lakhs, is there any need to file return. 5) is it correct that long term capital gain from property if invested one year prior to sale or within two years after sale is exempted from capital gain tax. what is the cost indexation for current fy. 6) if affirmative, is it necessary to declare this income in return. 7) any other option to save tax on capital gain. 8) what is last date for filing tax return. 9) can father file return return on behalf of his son, who is working abroad. 10) any other relevant/interesting info on the above issues.