GIC rates are available on pages like http://money.canoe.ca/rates/gics_5.html. Unfortunately, these all seem sourced from Fiscal Agents, which doesn't report all institutions (Ally and Hubert are missing, among others). Here's a few select GIC providers, for online, high rate cashable GIC shoppers.
GIC rates
  1yr 2yr 3yr 4yr 5yr

Early Cashability

Hubert - 2.25 2.45 2.60 2.85 yes - no interest within 1 year, otherwise 1.00%
Outlook 2.05 2.25 2.45 2.60 2.85 yes - 1% interest paid on withdrawn amount
Peoples Trust 2.20 2.60 3.10 3.10 3.50 no. Rates are for "direct" customers only, and are higher than those generally advertised.
Ally 1.75 2.00 2.25 2.50 2.75 yes. No interest < 1 year GICs, full interest on 1 yr GIC, 1.5% > 1 yr GICs
Maxa 2.05 2.40 2.80 3.05 3.30 yes, with 12 month interest penalty
ING 1.25 1.60 2.00 2.25 2.50 yes, 0.5% interest

Accelerate
Achieva

2.25 2.60 3.00 3.25 3.50 no
TD 0.95 1.15 1.35 1.55 1.85 no. Listed as an example of a Big5 bank and their low rates.