AFP has a quote from the secretary of Iran's National Council of Information:

http://afp.google.com/article/ALeqM5jnO2MFN5lQlTfnoPuB9i7rKGHZdA

(Thanks, post updated)

Supposedly uncensorwared now:

http://www.news.com.au/adelaidenow/story/0,22606,22434601-5005962,00.html

September 17, 2007 07:51pm

IRAN has unblocked access to the Google search engine and its Gmail email service after briefly filtering them owing to an "error", the Fars news agency reported.

"Due to an error, the Google site was filtered on Sunday evening but the error was corrected and now Google and its different sites like Gmail can be used," said an official from the state-run communications company.

Earlier today, Hamid Shahriari, the secretary of Iran's National Council of Information, had confirmed that the sites were being filtered, without providing further explanation.

Hi ,
last night around 00:00 o'clock google.com and gmail got filtered due to a technical difficulty in Iran . but I could access to www.google.co.uk and https://www.google.com/accounts/ServiceLogin?service=mail (for my gmail account) . now it's fixed . we can access to google.com and gmail.com .
[this problem took at least 10 hours to be fixed]

(Posted second update)

we've faced these errors million times dude :)

Sometimes Google is realy strange

i m blogging from iran,tehran. last night google and gmail and blogfa(main iranian bloging service) was filtered. But now everything is ok and they said that it was because of a technically fault

I think it might help since there is so much odd traffic coming from countries around the world...

adwordseditor.blogspot.com/2007/09/click-fraud.html

[URL unlinked – Tony]

Updates here :
http://www.mehrnews.com/fa/NewsDetail.aspx?NewsID=553437
this link is from mehr news agency .
it's said there was no error or something like that and they filtered google.com intentionally.
but the reasons is not explained yet.
  

Dear Sir
The error made lots of fuss through the country between those who use the computer and internet. But one thing is unknown for me , lots of Google services are not open for Iran , though Iranians are fond of google and its affiliated services .As an IRIB ISLAMIC REPUBLIC OF IRAN BROADCASTING tv reporter who responsible for a programme in the news on Information Technology I have no comment on why GOOGLE has closed services like Google earth sky ...
afrooznewsgmail.com ITIRIBNEWS.IR

Dear Afrooz
I think this is about why iran blocked google for iranian people not the google services but when our country do such things , how can we expect others to not close their services to us?

I think these guys are going to have a real proble cause www.ahmadinejad.com (Iranian president official website is filtered too).
and again with some search engines we have the problem of filtering but not Google .

Govrenment blocked several sites like google, orkut, facebook, flikr, technorati, blogrolling and etc. Google block several services for iranian people like google earth. We have blocked two ways. :(

Sepehr: Really? That's rather amusing, actually. :D

Yes, Google was filtered for about 24 hours also it has some errors in her page! I dont think these problems are normal! Today The Image searching is out of work and contains some errors!

Lets add it I`m in Iran Tehran now.

Yes, for few Hours...