As stated above, have a look at /var/log/messages or dmesg.
Is the network card configured statically or via dhcp?
Try to assign it a static ip address and reboot.
What kernel are you using?
I'm actually using the one from the v1.0 installer (22.214.171.124), and is
working almost flawlessly.
Mine boots from a "no brand" SD card in 20-25 seconds.