In the US, a one-month Gold subscription will rise for $7.99 to $9.99; three months from $19.99 to $24.99; and a full year from $49.99 to $59.99. Check Major Nelson's post for price changes in other regions.
If you want to extend your Xbox Live membership without paying the new higher costs, you have two choices: 1) you could renew your subscription for one year through Xbox.com for for $40; or 2) load up on prepaid subscription cards, like, now!
Update: Microsoft has informed Joystiq that the $99 price will not change for the Xbox Live Family Plan, also launching this November. So that's suddenly a better deal.