Hi and welcome to Just Answer!
Most likely - you are asked to sign W9 form - http://www.irs.gov/pub/irs-pdf/fw9.pdf
That form has two main purposes - (1) to provide the payer with your tax identification number - if you are physical person - in most situation the SSN is used; and (2) to certify that you are not subject to backup withholding - so the payer will not withhold any income taxes from the payment.
Without such certification the payer is required to withhold income taxes and remit to the IRS.
Then - the payer is required to report the payment made to you to the IRS - using form 1099-misc - www.irs.gov/pub/irs-pdf/f1099msc.pdf -your tax identification provided to form W9 would be used for that reporting.
The payer is also required to provide a copy of the form 1099-misc to the payee.
According to instructions -
File Form 1099-MISC, Miscellaneous Income, for each person to whom you have paid during the year:
--Gross proceeds of $600 or more paid to an attorney.
Under section 6045(f), report in box 14 payments that:
--Are made to an attorney in the course of your trade or business in connection with legal services, for example, as in a settlement agreement,
that reporting is to ensure that attorney's fees are properly reported on the federal tax return.
please let me know if you need any clarification or other tax related issues.