That won't be a problem we can come more than once in 3-6month intervals. Our friends would like that.
That's fine, but just be aware that each time you come back to the UK, you will have to prove that you are a genuine visitor and that you haven't or won't have spent more than 6 months in the UK in the last 12 months. It's not guaranteed that you will be let into the UK each time.
If the immigration officer feels you have spent too much time in the UK or that you are not a genuine visitor (i.e. are trying to live in the UK without a visa or will be working while you're here), they can refuse you entry and send you back to the US on the next plane home.
I will look into the Visa.
Just out of curiosity, which visa are you planning on looking into?
A work visa can be almost impossible to qualify for as you need to be sponsored by a UK company in order to get one and the company must prove there isn't anyone in the whole of the UK or EU capable of doing the job before they can hire you (and there are 500 million people in the EU). With unemployment so high right now and there being so many applicants per vacancy, it would be hard to find a job that no UK/EU citizen is suitable for.
Alternatively, there are a few 'shortage occupation' jobs for which you can get a visa more easily, but they are very specific in terms of job title and salary (such as medical consultants, science teachers, research scientists, etc.), or if you work for a US company with offices in the UK, you may be able to qualify for an Intra-Company Transfer visa.
The other options for a visa would be coming to the UK as a student to study for a degree, or falling in love with and marrying a UK or EU citizen and moving to the UK to be with them (I'm assuming you're not in a relationship with a UK/EU citizen though).
Do you (or your spouse/partner, assuming that's who you mean by 'we') have any claim to UK or EU citizenship (i.e. through parents/relatives)? If you could qualify for a UK or EU passport, you wouldn't have to worry about a visa for the UK.