[thelist] legal contract signature online? (USA)

[Stephen Rider]

For an apartment management web site, I have been asked if I could  
implement a function that allows a (prospective or returning) tenant  
to sign a lease online.  This would have to be a function that  
obtains a legally binding "signature" from somebody coming to the site.

The only example of this type of thing I can think of is the IRS  
allowing "digital signatures" now for tax returns.

Does anyone know about doing this?  Short of calling a lawyer, I'm  
not even sure where to start...

Thanks,
Stephen Rider

P.S. -- This applies to the United States -- mostly Chicago area.