last post on /forum/details.asp?mod_id=5679&offset=2 says
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For paying rent to wife, you will be entitled to claim exemption under Section 10(13A) of the Income Tax Act, 1961, read with Rule 2A of the Income Tax Rules, on the HRA received by you from your employer as long as you provide the rent receipts paid to your wife for staying in the house owned by her.
It is to be noted that the HRA benefit is denied only if the assessee stays in his/her own house or does not pay any rent for the accommodation occupied by him/her.
Your wife has to show the rental income received from you as 'Income from House Property'
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