Pricing issue

Hi friends

my problem is

For a scheduling agreements there are n number of deliveries.

suppose 1 delivery is made in Jan-2004 price is 100/1

2 feb-2005 200/1

3 april-2005 150/1

Now my requirement is to find the price of the item in a delivery when delivery was created.

i.e. in which tables can i find these price changes for a SA and also check for their validity dates..

We do not maintain pricingin delivery documents

Another problem is How to convert the currency i.e like

from INR to USD keeping in mind the exchange rate at the time of conversion

Thank you very much for ur help in advace

this is very urgent

please help me

regards

sree