networking - How to search for wireless networks?

I'm using Ubuntu 12.04. I tried with this

sudo iwlist eth0 scan

but this doesn't seem to work :(..It says "interface dosn't support scanning"
What to do? Please help..
I can't access Internet on Ubuntu.

Even I've mobile broadband usb, but even that doesn't get detected. Other pendrives get detected

More details

*-network UNCLAIMED
description: Network controller
product: Broadcom Corporation
vendor: Broadcom Corporation
physical id: 0
bus info: pci@0000:08:00.0
version: 01
width: 64
bits clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:c1500000-c1507fff

And more details:
lspci

00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Ivy Bridge PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4)
00:1c.1 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 2 (rev c4)
00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04)
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Thames XT/GL [Radeon HD 7600M Series]
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 05)
08:00.0 Network controller: Broadcom Corporation Device 4365 (rev 01)