Yes, the L4IGEA2 V1.1 supports Intel's Hyper-Threading technology. If you install a CPU with Hyper-Threading such as P4 3.06G on the MB, there is "Hyper-Threading technology" item in BIOS to let you enable or disable this new feature.
The L4IGEA2 V1.1 is built in CMI 9739 Audio chip with additional Dolby Digital decoder which supports up to 6 channels.
Yes, the L4IGEA2 V1.1 comes with Intel ICH4 which supports USB 2.0.
Yes, the L4IGEA2 V1.1 supports hard drive capacity up to 160GB.