The standard mileage offer for signing up for a mileage-earning credit card is slowly moving from 25,000 or 30,000 miles to 50,000 miles. Continental Airlines is the latest airline to increase its bonus for acquiring the OnePass Plus Card to 50,000 bonus miles for a limited time.

Through April 30, 2011, new cardmembers will receive 50,000 miles after first purchase, plus the $85 annual fee is waived the first year. Ongoing benefits include two Presidents Club passes every cardmember anniversary, first checked bag free on Continental when you purchase the airline tickets with your card, two miles per $1 spent on Continental and one mile per $1 spent on all other purchases.

Bottom line: With Continental merging with United, this is an offer frequent flyers should definitely consider. That extra 50,000 miles would be a nice addition to your combined United and Continental accounts.