3. Tax on rental income - this is due in October 31st of the following year. You fill out a FORM 12 (or form 11 depending on who you ask) to declare it. You calculate rental income minus interest paid on mortgage, minus any expenses eg insurance, utilities, maintenance, repairs. You can also deduct 1/8th of your captial allowances (fixtures and fittings).
You pay 42% tax on the total profit, plus 2% health levy. From 2006 onwards I think you have to be registered with the PRTB in order to claim back the mortgage interest.
4. Check out that your insurance on your rental property is still valid now that you have the place rented out.
5. When you sell it, you pay Capital Gains Tax on the profit. this is pro rata based on the proportion of time you rented it out of the total time you owned it. You can deduct Stamp Duty (I think), and solictors fees (cost of selling) from the profit to reduce the tax bill.