Map Product and Price by Date

Hello,

give me some hints please on how to get this thing working.

I have 2 Tables
Table Price contains the the Price for the product and productid - this looks likte the following example:

ID ActiveDate Price
1   20120101  9
1   20120220  11
1   20120401  10
1   20120601  12
2   20120101   9
2   20120201   8
2   20120301   9


Table Produkt

ID  ActiveDate
1    20120130
1    20120219
1    20120430
2    20120530

of course there is a primary key for each table...

So the Price is changing over time aswell as the product.
I need to map price and product so the activeprice needs to be within the activeproduct daterange.

Sample:
ID Price.ActiveDate  Product.Activedate  Price.Price
1   20120401            20120430                10

how do i do that?  
Thanks for the help!