My Try
{A1}=20060628
{A2}=20060701
{B1}=DATE(LEFT(A1,4),MID(A1,5,2),RIGHT(A1,2))
{B2}=DATE(LEFT(A2,4),MID(A2,5,2),RIGHT(A2,2))
{C1}=DATEDIF(B1,B2,"d")
Correct me if I am wrong :-)
{A2}=20060701
{B1}=DATE(LEFT(A1,4),MID(A1,5,2),RIGHT(A1,2))
{B2}=DATE(LEFT(A2,4),MID(A2,5,2),RIGHT(A2,2))
{C1}=DATEDIF(B1,B2,"d")
Correct me if I am wrong :-)