It sounds as if a major drainage system is required. Firstly, you need to establish that you have somewhere to drain the water to and then lay drainage pipes, probably in a herring-bone pattern, to remove the water. It might just be easier to build raised beds above the water level.

Is it water logged all the time or with the recent heavy rains? I found that aerating the soil helps drainage - so dig over the whole flower bed, adding compost, bark and some grit. That will help but as Bulbaholic has said, you might need garden drainage if this is a long term problem - the water has to go somewhere.

Usually water problems are because water is draining INTO the area rather than because of excess rain or lack of drainage. Is the bed at the bottom of a slope? If you then you need to interrupt the flow of water into the bed by digging a drainage ditch up ABOVE the bed. Sounds wrong I know, but it is correct.
If the water is going in from all other areas, ie the bed is at the lowest spot in the garden, then no matter how much drainage you put in, it will always be wet. In that case you need to raise the level of the bed so that the soil in it is above the wet layer.

Or you could try planting water loving or 'bog' plants instead - depending on size of your bed, some small salix (willow) together with Japanese water irises in pretty blues/purples, yellow English Flags, and loads of others! Could make a different patch in your garden by using the water rather than trying to get rid of it. For Bog plant variations try a good local garden centre or google for more names and varieties. I am sure there are some bog plant specialists out there who can help you get plants via the internet. Whichever you go for ... best wishes for the New Year!

As the previous people have suggested it might involve a serious mining project and best to find suitable shrubs which will thrive in the boggy conditions. You might try a hawthorn or the coloured stemmed cornuses, depending on the size of the site. If the worst comes to the worse, then why not make a natural wild life pool?

Lovely idea, jimmytheone! Use nature instead of battling against it ... a natural pond, with water loving plants ... frogs, dragon flies and all sorts will love it!!

To get you going try using the goypedia (A-Z) index at the foot of the page and click on B then on bog plants. There are 21 photos there and you will fing adverts popping up at the side with more suggestions. We'll look forward to hearing what you decide to do. Happy gardening in 2012.

Thanks to everyone for their advice. I shall try the easiest options first.