LONDON -- If you want to be eligible for a dividend payment, or if you're hoping a share price might drop disproportionately when the time has passed, you need to be aware of your all-important ex-dividend dates. We have already taken a look at three FTSE 100 companies going ex-dividend next week, and we have two more plus an important FTSE 250 company coming, too. These three will go ex-dividend next Wednesday, April 24 -- and all are offering yields well in excess of the FTSE's 3.1% average.

Legal & General (LSE:LGEN) (OTC:LGGNY)
Legal & General Group released full-year results early last month and announced a final dividend of 5.69 pence per share. That takes the insurance firm's full-year dividend to 7.65 pence, up 20% from 2011's 6.4 pence per share payment. Even though the Legal & General share price has gained about 40% over the past 12 months to 168 pence today, that total dividend still represents a yield of 4.5% -- and it's around 5.2% on December's closing price of 146 pence.

Forecasts for the year to December 2013 suggest a further rise, with analysts predicting a payment of 8.4 pence per share for a yield of 5%.

Centrica (LSE:CNA)
Utilities companies like Centrica, the owner of the U.K.'s British Gas brand, are generally considered cash cows when it comes to dividends. And at the end of February, the company announced a final dividend of 11.78 pence per share, which, added to an interim dividend of 4.62 pence, took the full-year payment to 16.4 pence per share.

Based on the year-end share price of 334 pence, that represents a yield of 4.9% -- though with the price having risen since to 377 pence, it's now closer to 4.4%. But that's still pretty nice from one of the most stable payers in the market.

Man Group (LSE:EMG)
In February, investment manager Man Group famously announced a final dividend of $0.125 per share, taking its 2012 full-year total to $0.22. Based on today's share price of 106 pence and using current exchange rates, that represents a massive 14% yield! But it was way in excess of underlying earnings, and it was not going to be sustained.

But Man Group's new dividend policy still looks attractive. The firm said it will pay at least 100% of its adjusted management fee income as its dividend, and 2012 figures suggest that could still amount to a yield of more than 6%.

Dividends like these can add nicely to your investment returns -- they can be spent or reinvested, according to your needs. Whether you're investing for income or growth, good old cash is always welcome. And that's why I recommend the brand-new Fool report "The Motley Fool's Top Income Share For 2013," in which our top analysts identify a share they believe will provide handsome dividend income for years to come. But it will only be available for a limited period, so click here to get your copy today.