I am a permanent resident of the United States. can i travel to and from mexico by land with out a passport?

I applied for a passport but the day of the appointment was to late for the days that i was going to travel. i went to the mexican consulate and they told me that i could go to Mexico with my birth certificate , and come back with just my permanent resident card.

That doesn't sound right.

NO, and i would not risk doing that at all... a permanent resident must travel outside of the US w/ a valid passport along with your green card and to be able to return you need that passport, so even if you can leave w/out it, you can't come back w/out it
and soon, if not already the US is requiring citizens to have passports to travel by land, plane and boat

You need a passport.

A passport is required

Sorry, previous answers are incorrect and the consulate, of course, is spot on. The following is taken directly from the U.S. Customs and Border Protection website. The link is in the "Sources" section.

QUOTE
For Travelers Other than U.S. and Canadian Citizens

All existing nonimmigrant visa and passport requirements will remain in effect and will not be altered by the changes that are implemented on January 31, 2008.

U.S. Lawful Permanent Residents
Permanent Resident Card (I-551) or other valid evidence of lawful permanent residence is required.

You can Pay $97 and jump through all the hoops and red tape and spend months getting your pass port or-----walk back and forth across the Rio Grande all day long every day for nothing.

I have no idea what you need to go to Mexico, but to come back to the US, you need your green card. You do NOT need your home country's passport if you are a permanent resident.

In case you don't know yet, you might to into Mexico without a problem, but on the way back, as of today, you will be asked for a passport or other documents as proof of US citizenship. Check the news section in the yahoo or msn homepages, I saw a video that talked about it this very morning.
Luck

By the way, this is valid if you travel by land or by sea. The required documents vary according to age, so they are not always the same ones. The article did not mention anything about the airlines.

UPDATE I found the source I mentioned earlier, hope it is useful.
http://www.npr.org/templates/story/story.php?storyId=18577097&sc=YahooNews&ft=1&f=100 3