Re: the tick and tapeworm question. I just arrived last week, New York/Kennedy to London/Heathrow, and my vet used Frontline (a liquid applied to the back of the neck, made by Merial) for the tick treatment and Drontal (in a pill form; made by Bayer) for the tapeworm, and I got through just fine. Keep in mind these are two different treatments, and there are two different sections to be filled out by your vet on the paperwork (one for tick, one for tapeworm).
A few other tips, from my recent experience:
1. Do not rely on what the airline tells you about the PETS scheme. I was given incorrect information by British Airways and it cost me time and money when I landed. If you have questions, go straight to the horse's mouth: DEFRA.
2. Someone upthread asked about flying their pets in through unapproved routes. Personally, I think this would be madness. Once you land, the quarantine people have your pet, and they can refuse to release it to you if they so choose. They can also make you pay extra fees, or make the pet stay longer. I know it's a pain if you're not near an approved airline or city on either side of the pond, but I would not risk it. They are serious about these regulations.
3. If anyone suggests that you no longer have to have the paperwork signed off by a USDA vet -- and I don't mean your regular vet, who can fill in the individual sections, but an actual EMPLOYEE of the USDA -- they are wrong. This is what BA told me. It cost me an extra 4 hours and 60 quid on the other side to have an official vet sign off on the paperwork once I got to London.
4. MAKE SURE YOUR CRATE IS THE RIGHT SIZE. When they say that the animal's extremities cannot touch the walls of the carrier, they mean it. When I got to BA cargo at Heathrow, they took one look at the (very large) cat carrier I was using for my 16-pound cat and said "no way." Luckily they had a dog carrier there and I was able to trade my original carrier for it, but it tacked an extra $500 onto my cat's ticket because of the extra volume and weight. Better to err on the safe side.
5. Ask your vet to write out dates instead of using the numbered shorthand on the paperwork. For example: October 3, 2005 instead of 10/3/05. In the British shorthand, that date would be 3/10/05. Writing out the actual name of the month saves on confusion.