Hi Kaye,
Most agricultural feed merchants will supply pig feed (just ring to check) or you may want to grow/make your own. Have a trawl through the pig section - I'm sure there's a post on that very subject.
As for what breed is best
Everyone has their own personal favorites
Large blacks are chilled out pigs, tamworths (IMO) are a bit mental, some are better for bacon and hams while others are better for pork - but they're all GREAT for churning up ground !
Maybe best to get a couple of cross breed weaners for your first attempt - they don't cost as much as pedigree's, especially if you don't want to go down the breeding route. I paid £30 each for cross breed weaners but I think the pure breeds are upwards of £50 each - depends where you are.
Good luck and do let us know what you end up getting