Below you can find the direct links to the iPhone Firmware Files for every released firmware so far, I will keep this updated as it changes.

1.0.0 - iPhone1,1_1.0_1A543a_Restore.ipsw
1.0.1 - iPhone1,1_1.0.1_1C25_Restore.ipsw
1.0.2 - iPhone1,1_1.0.2_1C28_Restore.ipsw
1.1.1 - iPhone1,1_1.1.1_3A109a_Restore.ipsw
1.1.2 - iPhone1,1_1.1.2_3B48b_Restore.ipsw
1.1.3 - iPhone1,1_1.1.3_4A93_Restore.ipsw
1.1.4 - iPhone1,1_1.1.4_4A102_Restore.ipsw