There are a number of ways. You could try this, assuming your data in
Sheet2 extends from A1 to A1000, and that the first cell you want to
check in Sheet1 is A1, enter this in B1:

=IF(ISNA(VLOOKUP(A1,Sheet2!A$1:A$1000,1,0)),"no"," yes")

Copy this down column B by double-clicking the fill handle (the small
black square in the bottom right corner of the cursor with cell B1
selected).

Hope this helps.

Pete