I have a spelling checker,
  It came with my PC;
  It plainly marks four(for) my revue(review)
  Mistakes I cannot sea(see).
  I've run this poem threw(through) it,
  I'm sure your(you're) please too no,(pleased to know)
  Its(It's) letter perfect in it's(its) weigh(way),
  My checker tolled me sew.(told me so.)
ARE THERE ANY MORE CORRECTIONS TO BE MADE?

Hi,

The revised spelling looks fine to me.  I'm a writer/editor who
professionally copyedited for about 10 years, if you're interested in
my credentials.

I would, however, punctuate the verse differently, and make it as
follows:

I have a spelling checker,
It came with my PC.
It plainly marks for my review
Mistakes I cannot see.
I've run this poem through it;
I'm sure you're pleased to know
It's letter perfect in its way -- 
My checker told me so.

You might be interested in knowing that this poem was originally
written by Jerrold H. Zar under the title of "Candidate for a Pullet
Surprise."  You can find variations of it all over the Internet.  The
link below takes you to what is purported to be the original version:

Candidate for a Pullet Surprise
http://tenderbytes.net/rhymeworld/feeder/teacher/pullet.htm

And here is a college professor's corrected version:

Candidate for a Pulitzer Prize
http://cs.ua.edu/440/Handouts/Candidate%20for%20a%20Pullet%20Surprise-Corrected.htm

I tracked down information about the poem by using the Google search
term "my checker tolled me sew" and by following various links from
the sites I found.
://www.google.com/search?q=%22my+checker+tolled+me+sew%22

Best wishes,

mvguy (who proofread this answer carefully after spell-checking it)

"planely" maybe?

"I have a spelling checker,/ It came with my PC." is a comma splice. 
Two independent clauses cannot be joined by a comma.  They need a
coordinating conjunction between them, or they need other
punctuation--a semicolon or a period.  You could even justify a colon,
although that use is out of fashion (on account of ignorance, not
inaccuracy), or stretch to an em dash, but you can't defend a comma.

Would we not also hyphenate "letter-perfect"?

Avoiding the comma splice would be preferable (OK, mandatory) in
formal writing.  In informal writing, however, comma splices are
sometimes acceptable, in my opinion.  Here are some grammarians who
agree:

When Is a Comma Splice NOT an Error?
http://www.grammartips.homestead.com/spliceok.html

Comma Splices
http://athena.english.vt.edu/~IDLE/Gym2/workout17/w17.stretch2.html

Unravelling the Comma Splice
http://www.ncte.org/pdfs/members-only/ej/0873-march98/EJ0873Coming.PDF

The hyphenation of "letter perfect" is a matter of style.  The Chicago
Manual of Style would not call for a hyphen in such a predicate usage,
but it does call for a hyphen when the two words are used as an
adjective before a noun.  Thus "the poem is letter perfect" but "the
letter-perfect poem."   (CMOS, Fourteenth Edition, page 221.)  I
believe that the current Associated Press style would use a hyphen in
both cases, but I don't have a copy in front of me.

As a free-form bit of poetry, I doubt that punctuation is really
needed after each line.  That, too, may just be a style choice.  I
read this column on punctuation in poetry and thought I'd pass it
along.  I do agree with the author's line about knowing the rules of
punctuation before discarding them.
http://www.writersmonthly.com/wm_library/poets_workshop/how_to_punctuate.html

I'd say letter perfect *would* require a hyphen as "it's" infers "the
poem" and thus needs the adjectival form.

p.s.  Sorry, I forgot to add that if you're going with an
anti-punctuation style, I'd omit the hyphen with letter-perfect. 
How's that for waffling?
I'll try to locate a reference on this in a prose situation when I
have a sec.

compound adjectives after a noun:  http://www.thebizjournal.com/articles/209.html