There may be a need for guest-worker legislation that would allow farmworkers to enter from Mexico on temporary visas. That does not, however, justify allowing line-jumpers more freedoms than those who attempt to go through this country's long and arduous legal immigration process.
Personally, I'd support an amnesty for illegal aliens iff it was modeled after the RIAA's "amnesty" program: if an illegal alien goes to a government office before Dec 31, 2003, gives a photograph and fingerprints, and signs a form acknowledging their nationality and agreeing that if they are caught in this country illegally after Jan 1, 2004, they'll go to prison for five years; then after they've signed that form they'll be allowed to go home (i.e. their country of origin).