April 2009 Update: I have collected much more data, and now have improved letter frequency. How accurate is it, though? It should be accurate enough, but look here if you're really interested in accuracy.

Here you will find a letter frequency graph. The frequency there is different from here because I used a slightly different data set. However, both are reliable enough. 
	
	Character Frequency:   e t a i o n s r h l d c u m p f g y w b , . v k " - 0 ' x j 1 z 2 q 9 5 3 8 4 7 : 6 ) ( $ ; | ? / ! & [ ] % _ @ > = * < + # ` ^ { } ~ \
	Letter Frequency:      e t a o i n s r h l d c u m f p g w y b v k x j q z 
	Punctuation Frequency: , . " - ' : ) ( $ ; | ? / ! & [ ] % _ @ > = * < + # ` ^ { } ~ \
	Number Frequency:      0 1 2 9 5 3 8 4 7 6
	Big Key Frequency*:    SPACE SHIFT DELETE ENTER TAB

	*Approximate order. SHIFT is currently not testable, and DELETE depends on the user's error rate.

Digraph Frequency: 
th he in er an re on at en nd ha ou or st is ng ed it to es te ar ti hi se al as nt le ve 
of me ea ne ll ro de co ri li be el ra ce ch ho no om io ma ic ut ta ur et ot si wh us il 
ly wa ca la pe fo lo wi ow so ad ge ac di ee ec un ns rs tr ss ai we im id sh yo nc pr ol 
mo em ie ul po ct rt os ld ke

Trigraph Frequency: 
the ing and hat ion her tha ent for his tio you ere ter thi all ver ith wit not ate ati 
was rea nce ers eve are con one ess out res ted hin ome ave int our ist sta ill ear men 
ght com but ons est tin hav ive igh oul pro uld ain ore hou ect man oun per oth rin ble 
der sti rom ove fro han whi nte und tho str red ame ste ide tur had use hen ant ine art 
ugh whe ind hey eat wer cou nde end ort now him

Spanish letter frequency: e a o s r n i d l c t u m p b g y v q h f z j x w k
from here

German letter frequency: e n i s t r a d h u g m c l b o f k w v z p j q y x
from here

French letter frequency: e a s i t n r u l o d c m p v q g f b h j x y z k w
from here

Dutch letter frequency: e n t a o i r d s l g h m v b w k u p c ij z j f é x
from here

Other letter frequency sites, ordered by reliability and detail: A M Research letter frequency Wikipedia letter frequency

word frequency Letter (and other stuff) frequency, at the bottom due to dubious accuracy
I did NOT get my letter frequency from any of these sites. I created a large text file with a variety of text and counted letter frequency with a program that I wrote. I made this web page because none of the above sites were detailed enough for me, and I thought others might feel the same way. For more information, see Theory of Letter Frequency.