Certificates Question

Hi,
I am a total newbie at security, just trying to learn the
basics. So pardon me if my questions are naive.

1) I navigate to mail.yahoo.com using IE6. I see
a golden padlock on the status bar. I click on it to the
see the certificate. In the details tab - I click the public
key field - In the value column I see "RSA (1024 bits)
But if I copy the value from below - 30 81 89 .... 00 01",
I see it's actually 140 bytes (1120 bits) & not 1024 bits.
If I go to the same site using Firefox 2.0.0.3 & look
at the certificate, the subject's public key field shows
"Size: 140 Bytes / 1120 Bits". Why does IE show 1024 instead of 1120.

2) I am looking at a tutorial at
http://www.freesoft.org/CIE/Topics/140.htm
In the paragraph "X.509 Certificates", look at the first
certificate. In the certificate look at the
"Subject Public Key Info:"

RSA Public Key: (1024 bit)
Modulus (1024 bit):
00:b4: ..........
.................
.........7e:41:8f

The key is actually 129 bytes or 1032 bits &
not 1024 as stated. Why the discrepency - is it because
of the leading "00"?