how to browse android sd card on a mac?

How are you trying access the card? If you connect the usb the card should show up on your desktop.
 
...and make sure your change the connection that pops up when you connect to your computer from charge only to what ever you need it to.

If on charge only you won't see your card

Wow I just saw the OP Date ha ha this is an old thread
Sent Using TaPaTaLk
 
I developed an app called Browsix where you can copy files from and to your phone while using a regular browser. Just try it out. Let me know if you want more details.