iPhone Firmware (.ipsw)

Jailbreak / Unlock Availability:
All iPhone/3G/3GS firmwares up to v3.0.1 have been jailbroken and their most recent basebands unlocked. PwnageTool is out for firmware v3.1.0, but RedSn0w releases are still to come. The newly-released firmware version v3.2.0 has no compatible modification tools at present

iPhone

v1.0.0 - Modem FW 03.11.02_G
v1.0.1 - Modem FW 03.12.08_G
v1.0.2 - Modem FW 03.14.08_G
v1.1.1 - Modem FW 04.01.13_G
v1.1.2 - Modem FW 04.02.13_G
v1.1.3 - Modem FW 04.03.13_G
v1.1.4 - Modem FW 04.04.05_G
v2.0.0 - Modem FW 04.05.04_G
v2.0.1 - Modem FW 04.05.04_G
v2.0.2 - Modem FW 04.05.04_G
v2.1.0 - Modem FW 04.05.04_G
v2.2.0 - Modem FW 04.05.04_G
v2.2.1 - Modem FW 04.05.04_G
v3.0.0 - Modem FW 04.05.04_G
v3.0.1 - Modem FW 04.05.04_G
v3.1.0 - Modem FW 04.05.04_G
v3.1.2 - Modem FW 04.05.04_G

iPhone 3G

v2.0.0 - Modem FW 01.45.00
v2.0.1 - Modem FW 01.48.02
v2.0.2 - Modem FW 02.08.01
v2.1.0 - Modem FW 02.11.07
v2.2.0 - Modem FW 02.28.00
v2.2.1 - Modem FW 02.30.03
v3.0.0 - Modem FW 04.26.08
v3.0.1 - Modem FW 04.26.08
v3.1.0 - Modem FW 05.11.07
v3.1.2 -

iPhone 3Gs

v3.0.0 - Modem FW 04.26.08
v3.0.1 - Modem FW 04.26.08
v3.1.0 - Modem FW 05.11.07
v3.1.2

Additional Downloads

AT&T US - Vesion 5.0

Bootloader - Version 3.9
Bootloader - Version 4.6

QuickPwn - Version 2.2.5
RedSnow - Version 0.8
PwnageTool - Version 3.3.1

Glossary

Firmware - The operating system on the device that can be changed through downloadable updates.
Jailbreak - The process by which a device is modified to allow unsigned code to be run.
Unlock - The removal of SIM restrictions on the modem, allowing the use of the phone on any carrier.
Baseband - The software portion of the modem in the iPhone that can be changed through downloadable updates.
Bootloader - Software that loads either the baseband or operating system into memory before execution.
QuickPwn - Application used in the firmware v2.x era to jailbreak Apple devices. Superceded by RedSn0w.
Recovery mode - A special mode in the device allowing firmware restoration; in this mode, the screen of the device shows a graphic.
DFU mode - A special mode in the device that bypasses the loading of the operating system for recovery purposes; in this mode, the screen of the device is blank.