mallett_sj,
The instructions for the I-134 tell you what information the letter of employment should contain. Such a letter would not be required if I-134 is not required, if one's income is from sources other than employment, or if one is self-employed. There may be some other exceptions as well.
The IRS would have a copy of your last years tax return, if you filed one.
Yodrak
QUOTE(mallett_sj @ Aug 2 2006, 01:56 PM)

Hi everyone i just want to ask a question, first question is the proof of employment from your boss what must it include on it? and is it required? Second question is where can i access last years tax return? Thanks for your Help.