in lucid, with grub2, add acpi_osi=\\\"!Windows 2006\\\" to /etc/default/grub (or to /boot/grub.menu.lst, under boot parameters for kernel to be loaded).

This fix, however, did not work for me. I still boot up, login, have frequency scaling working properly (governor ondemand -d 1000000 -u 2000000) for a period of time (which varies), and then cpu falls to lowest freq and is stuck there. (Forum browsing suggests this may be DSDT-related. Sadly, the Ginkel Fix is no longer available.) 

After this occurs, I get the following readings

(1) cpufreq-info (note the maddeningly persistent "between [minimum] and [minimum]"):

analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0 1
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us.
  hardware limits: 1000 MHz - 2.00 GHz
  available frequency steps: 2.00 GHz, 1.67 GHz, 1.33 GHz, 1000 MHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1000 MHz and 1000 MHz.
                  The governor "userspace" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz (asserted by call to hardware).
  cpufreq stats: 2.00 GHz:2.16%, 1.67 GHz:20.58%, 1.33 GHz:5.83%, 1000 MHz:71.43%  (815)
analyzing CPU 1:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0 1
  CPUs which need to have their frequency coordinated by software: 1
  maximum transition latency: 10.0 us.
  hardware limits: 1000 MHz - 2.00 GHz
  available frequency steps: 2.00 GHz, 1.67 GHz, 1.33 GHz, 1000 MHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1000 MHz and 1000 MHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1000 MHz (asserted by call to hardware).
  cpufreq stats: 2.00 GHz:2.02%, 1.67 GHz:0.21%, 1.33 GHz:4.80%, 1000 MHz:92.97%  (438)

(2) cat /proc/cpuinfo

processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 14
model name	: Genuine Intel(R) CPU           T2500  @ 2.00GHz
stepping	: 8
cpu MHz		: 1000.000
cache size	: 2048 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 2
apicid		: 0
initial apicid	: 0
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 10
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc arch_perfmon bts aperfmperf pni monitor vmx est tm2 xtpr pdcm
bogomips	: 3995.08
clflush size	: 64
cache_alignment	: 64
address sizes	: 32 bits physical, 32 bits virtual
power management:

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 6
model		: 14
model name	: Genuine Intel(R) CPU           T2500  @ 2.00GHz
stepping	: 8
cpu MHz		: 1000.000
cache size	: 2048 KB
physical id	: 0
siblings	: 2
core id		: 1
cpu cores	: 2
apicid		: 1
initial apicid	: 1
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 10
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc arch_perfmon bts aperfmperf pni monitor vmx est tm2 xtpr pdcm
bogomips	: 3994.66
clflush size	: 64
cache_alignment	: 64
address sizes	: 32 bits physical, 32 bits virtual
power management:

(3) lscpu:

Architecture:          i686
CPU(s):                2
Thread(s) per core:    1
Core(s) per socket:    2
CPU socket(s):         1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 14
Stepping:              8
CPU MHz:               1000.000
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              2048K