Ladies (and Gents!)
If you have a surestart childrens centre near you I have to recommend a visit. At my local one all the activites are free - things like messy play, baby sensory, rhyme and story time, toy library.
If you check the surestart website it gives the locations of centres (sorry don't know how to do links!)
DS has a great time there - nice bunch of mums too - well worth a look.