Find below direct links to all iPhone firmware that has been released. List will be updated as new firmware gets released.

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
2.0.0 (2G): iPhone1,1_2.0_5A347_Restore.ipsw
2.0.0 (3G): iPhone1,2_2.0_5A347_Restore.ipsw
2.0.1 (2G): iPhone1,1_2.0.1_5B108_Restore.ipsw
2.0.1 (3G): iPhone1,2_2.0.1_5B108_Restore.ipsw
2.0.2 (2G): iPhone1,1_2.0.2_5C1_Restore.ipsw
2.0.2 (3G): iPhone1,2_2.0.2_5C1_Restore.ipsw
2.1.0 (2G): iPhone1,1_2.1_5F136_Restore.ipsw
2.1.0 (3G): iPhone1,2_2.1_5F136_Restore.ipsw
2.2.0 (2G): iPhone1,1_2.2_5G77_Restore.ipsw
2.2.0 (3G): iPhone1,2_2.2_5G77_Restore.ipsw
2.2.1 (2G): iPhone1,1_2.2.1_5H1_Restore.ipsw
2.2.1 (3G): iPhone1,2_2.2.1_5H11_Restore.ipsw
3.0.0 (2G): iPhone1,1_3.0_7A341_Restore.ipsw
3.0.0 (3G): iPhone1,2_3.0_7A341_Restore.ipsw
3.0.0 (3GS): iPhone2,1_3.0_7A341_Restore.ipsw
3.0.1 (2G): iPhone1,1_3.0.1_7A400_Restore.ipsw
3.0.1 (3G): iPhone1,2_3.0.1_7A400_Restore.ipsw
3.0.1 (3GS): iPhone2,1_3.0.1_7A400_Restore.ipsw
3.1.0 (2G): iPhone1,1_3.1_7C144_Restore.ipsw
3.1.0 (3G): iPhone1,2_3.1_7C144_Restore.ipsw
3.1.0 (3GS): iPhone2,1_3.1_7C144_Restore.ipsw
3.1.2 (2G): iPhone1,1_3.1.2_7D11_Restore.ipsw
3.1.2 (3G): iPhone1,2_3.1.2_7D11_Restore.ipsw
3.1.2 (3GS): iPhone2,1_3.1.2_7D11_Restore.ipsw
3.1.3 (2G): iPhone1,1_3.1.3_7E18_Restore.ipsw
3.1.3 (3G): iPhone1,2_3.1.3_7E18_Restore.ipsw
3.1.3 (3GS): iPhone2,1_3.1.3_7E18_Restore.ipsw