Before my birth I had name,
But soon as born I changed the same;
And when I'm laid within the tomb,
I shall my father's name assume.
I change my name three days together,
Yet live but one in any weather.

In case anyone is still trying to get this one, here's a clue and the answer:

Hint 1: <span class='standouttext'>Spoiler : </span><span class='spoiler'> The biggest clue is in the line "I change my name three days together" </span>

Hint 2: <span class='standouttext'>Spoiler : </span><span class='spoiler'>OK, it's not the names of 3 days of the week - but what other 3 names can apply to 3 days in a row? Have a good think before rushing on to the answer! </span>

Answer:

<span class='standouttext'>Spoiler : </span><span class='spoiler'> Before my birth I had name, (tomorrow)
But soon as born I changed the same; (today)
And when I'm laid within the tomb,
I shall my father's name assume. (yesterday)
I change my name three days together,
Yet live but one in any weather. (today is the answer. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> )
</span>