I haven't done it since 2001. There was a free bus then, not sure now. I can't remember how long it took, but I'd allow an hour, in addition to regular check-in time. Note that internal flights in SthAm are 20kg limit, not the 2 x 32kg from the US. If you have it all on the one ticket you should be able to take 2 x 32 on the internal, but not if it's a separate ticket, or you break the journey overnight.

D

Just did it 2 weeks ago. Taxi fare was about 135 ARS if I remember correctly. As for the lugguage in AEP LAN ignored our overweight but in MDZ we had to pay for - still cheap!

I did this in December. If you have 2 hours or more to kill, you can save money by taking the bus, Tienda de Leon or something like that. It is an express bus that costs 45 pesos one way. It is about 50 km between the airports, so you get to see a little of BA.

I just did this this past month, going to and returning from Mendoza. The name of the bus company (they also run cars, "remises" and minivans, "transportes", for a higher cost) is Manuel Tienda Leon. Just head for the surface transportation area of the EZE airport and look for their logo, a sort of friendly lion's head. The staff at the desk where you buy the ticket will direct you to their bus stop in the confusion outside the terminal. Here's their website:
<http://www.tiendaleon.com.ar/home/empresa/que_hacemos_1.asp>
The ride between Aeropuerto Ezeiza (EZE) and the Aeroparque takes about an hour by bus, including a stop at Leon's own downtown bus stop, and costs AR$45, or about US$15. The buses are clean and pleasant. As with all situations in Argentina, Spanish language skills are helpful, but not absolutely necessary, especially if you have an open mind and aren't afraid to look a little foolish at times.