This song,
especially the intro, is not 100% correct. I taught myself this and it is probably wrong
in a few areas. I did not write every single strum, just the chord changes. If you love
the song enough to learn it, you should be familiar with all of the strumming patterns.
Anyway, I hope you enjoy these tabs. They are the first ones I have written.
-I have edited the chorus, I noticed the first part is a little different and I only 
repeated what should have been only the 2nd part-

Intro
-------------------------|
-------------------------|
-5--5--4--5--------------|
-------------------------|
-3--------3--10--5--7--3-|
-------------------------|

Go to rhythm of song...
-----------------------------|
-----------------------------|
-5--7--12--7--9--7--5--7--12-|
-----------------------------|
-3--5--10--5--7--5--3--5--10-|
-----------------------------|

Verse                              then...
-----------------------------      ---------------|
-----------------------------      ---------------|
-5--7--12--7--9--7--5--7--12-      --12--10-9--7--|
----------------------------- x2   ---------------|
-3--5--10--5--7--5--3--5--10-      --10--8--7--5--|
-----------------------------      ---------------|

At 0:24
--------    -----|
--------    -----|
--5-----    --5--|
-------- x2 -----|
--3--3--    --3--|
-----3--    -----|

Verse

Chorus
---------------------------------|
---------------------------------|
--5----------------5-------------|
---------------------------------|
--3--5---0---3-----3--5---7---3--|
-----5---0---3--------5---7---3--|

Post Chorus
-----------------------|
-----------------------|
--5~---12--14--9--7----|
-----------------------| x2
--3~---10--12--7--5----|
-----------------------|

1:20
----------|
----------|
--5--7----|
----------|  Alternates between these 2 chords until chorus at 1:34ish.
--3--5----|
----------|

Chorus

Then
---------------------|
---------------------|
--5--12--9--7--9--7--|
---------------------| x2
--3--10--7--5--7--5--|
---------------------|

2:03ish.  1 guitar plays above and 2nd guitar plays this...
------------|
------------|
--5---------|  It is only these 2 chords up until the final chorus at 2:46
------------|
--3---3-----|
------3-----|

Chorus

Final Riff
-------------------------------------------------|
-------------------------------------------------|
--12--9--12--9--12--10-9--7--12--9--12--9--7--5--|
-------------------------------------------------| x2
--10--7--10--7--10--8--7--5--10--7--10--7--5--3--|
-------------------------------------------------|

Again, this is not 100% right.  I love The Wonder Years, and this song. I taught myself
and I made mistakes.