802.3-2000 ( 802.3 asof year 2000) is a subset of 802.3-2008 ( 802.3 asof year 2008)
Basically , all new ethernet standards come under the same document ( 802.3) , and
they are added as new clauses .
For eg, as of 2003 , It had 54 clauses ( something like 54 chapters in 802.3 Book)
then in 2006 , 10GBase-T (10Gbps on UTP cable) was done , so it was added as
clause 55. later 10GBase-LRM was defined , it was added as some clause , etc...
for eg. 802.3ae represents new clauses 44 to 54 i guess , and other changes to
previous clauses bcoz of them.
The future standards like 40Gbps/100Gbps ethernet will be added as clause 80 to clause 90 i guess .
so the document gets bigger and bigger and ... , as the time goes by.
Also if your company has access to IEEE xplore , then u can download any
IEEE standard for free .