I’d have to say that there really is no “standard” format that is always used by everyone in the U.S. who writes a business letter. And of course, when using business stationery that already includes company name, address, etc., the writer’s return address is not necessary (but the date still is).

Some people line up everything along the left margin. Personally, I like to line up the date (and closing) so that they start in the center of the page.

As far as Bonnie’s comment about “always” using a colon after the salutation, there is an exception (— of course: it’s English!). It is acceptable to use a comma instead of a colon if the business letter is “informal” and if the writer and addressee are “friendly.”

For example –

Dear Mr. Smith: (formal and common in business writing)
or
Dear Ed, (informal and sometimes appropriate)

At least, that’s been my experience.

As well it is standard practice for business letters in the U.S. to be laid out using “full block” format. Using this format, the entire letter is left justified in the order that Cassie suggests. This is the only format I ever use for business writing.

The writer’s address and date should go on the right and the recipient’s address on the left, side-by-side (old style rules normally put the writer’s address higher on the page, and the date lower than the recipient’s address, to avoid having to type two columns on a manual typewriter – not a problem nowadays; the recipients address should of course be aligned to fit in the window if using windowed envelopes). I can’t imagine any circumstance in which it would appropriate to use a colon after the salutation…?

I agree: The “enclosure” line goes at the bottom of the letter.

I learned a slightly different method, though, for formatting correspondence.

1. writer’s return address
2. date the letter is being written
3. name, title, and address of recipient
4. a RE or subject line if desired
5. salutation (with colon or comma, depending on relationship)
6. body of the letter
7. closing and signature
8. initials of typist*
9. notice of enclosure (if any); item(s) enclosed/attached may or may not be spelled out. I do not underline “Enc.”
10. notice of cc and bcc (if any)

* randomjohn mentioned including the author’s initials with the typist’s initials. I learned to just note the typist’s initials; however, if you want to include both, it would be: “RQJ:mfs” (author first).

In the invoicing business , bills of shipping etc – you can never be told what is enclosed too many times.

I saw a great sign on a shop in London the other day. One shop said “Established 1869″ – the shop next door read ” We’re Never Established!!” – that’s funky!