using column name as row value

i all,
I have a requirement and unable to solve this problem. I want ur urgent help. The problem is that there is a table like this

Allowance1 Allowance2 Allowance3 empid

12 13 14 56
15 45 89 89
78 102 89 20

I want to change this as

empid allowance amount
56 allowance1 12
56 allowance2 13
56 allowance3 14
89 allowance1 15
89 allowance2 45
89 allowance3 89


Like this one I want as outcome


Please help me in getting this output

select empid, 'allowance1',allowance1
union
select empid, 'allowance2',allowance2
union
select empid, 'allowance3',allowance3
from table