To see what Buffet owns

Goto http://www.sec.gov/ --> search --> 'EDGAR full text search' which leads to their MainAccess page
Click on Advanced Search page.
Enter in:

• Form type: "13F-HR"
• Central Index Key (CIK): 1067983
• Current end date, and start date sometime in the past.

The results are given in tables. Column 5 (Shares or Principal Amount) is the important one. eg:

Column 1	Column 5
------------------	--------------------
Johnson & Johnson	Shares or Principal Name of Issuerer Amount $
	13,509,591
	325,300
	9,087,200
	792,000
	575,000
	3,897,300

Add up all the numbers in this column for the total number of shares owned by Berkshire. Compare it with the numbers from different quarters to see if they are buying or selling.

13F forms are published within 45 days after the quarter end.

Or else, just google for 'berkshire hathaway 13F' or 'buffet holdings' to see if someone else has already done the work.