sanatogen do one, which i took (when i remembered)
a good diet should be all you need but it doesnt hurt to take supplements.
Just make sure that they are pregnancy ones!
And no, you dont have to tell GP (unless you have any conditions whereby you shouldnt be taking supplements) , in fact GPs dont really have anything to do with pregnancy related issues, your midwife does. they may ask if you are taking anything.
Pregnacare - if its spelt like that, is quite good, includes vitamins, minerals and folic acid. But only take it if you feel weak or tired as diet should be adequate.