Hi I went to Blackpool at the beginning of June for a concert at Winter Gardens (opera house) and it was mildly busy. I can imagine with the hot weather that the crowds have increased a little but it should still be bearable. It is VERY tacky....all the seaside shops with all of the typical hen and stag night goodies!
However there are some very decent attractions. We took a wander down the pier to the arcade and ate fish and chips on the way, such a typical seaside moment! There's also a huge indoor pool/water fun area (don't know how much it costs, but it looks a good one for kids) and the pleasure beach (£29 for a wristband for the whole day, or a minimum of £25 pp for individual ride tickets).
i can imagine that the pleasure beach is pretty busy this time of year. But there's some lovely ice cream places, and lots of seaside bars and cafes to get a refreshing drink.
The high street is at the north end and is generally not as busy (the south of the seafront and beach is the real seaside bit).
There are trams that run up and down the beach all day, I'm not sure how much they cost but its an awfully long walk from the very North (where the main rail station is) to the South (where the pleasure beach is), and they look quite good fun.
Are you staying for more than a day? Do you need any tips on hotels?? Travel?
HTH