Hi there DtM. You won't believe how many times I edited that dang post to make my meaning clearer, and still I didn't quite accomplish it.
Anyway, yes, the figures are monthly. The ones on the left side are actually bonafide $USD monthly amounts (or at least, annual amounts divided by 12).
Yep! You hazarded correctly; $6,599.87 is our annual property taxes stateside (2008 assessment just in.) We're going to rent the first 1-3 years (until the US real estate market turns around, at which time we'll put the US house up for sale) in A-C Band, London. Even then, I'm not thrilled about owning a house again and all the attendant upkeep.

My £450 pw is for a 2-3 bedroom roughly 1/4 the size of our US house (but it's now just me and DH, and frankly, I'll be glad to be shod of 3455 sqft, 4bed, 4bath, study, gameroom, 2 living rooms, dining room, media room.) It will be comparable in neighborhood and as importantly (to us) comparable to the square footage of space that we've actually used the last few years (which is about 1/3 of the house and not the entire upstairs or formal living room at all. Still, I know it may feel pokier at first, but comparable apartments here (2beds, 900sqft) are around $1600, so I'm not blown away.
Next, how 'bout those utility bills, eh! $68 of that is city statutory minimum for water/sewage/trash for a free-standing single-family home (in other words, what the council tax would be for). It's fixed and goes up from there during the year, depending on your water usage and how much you, uh, flush.

. The rest? Well, freakin' Enron, freakin' EXXON, freakin state politicians with their hands in the utility companies' pockets. Every time TXU Electric cries that the need to raise their rates, it swoops thru like greased lightning...3 weeks later the papers announce "record" profits for them. Hmmph. 10 years ago when I bought this house, my utilities (not counting water) averaged about $90/month.
I've called, read, written, calculated and pestered London-based bloggers and keep coming up with about £73 total for gas, elec, water for a 2-bed, 1 bath flat for 2 people. It could be more, but if it even approaches £150, I'll eat my Stetson.

.
Moving on: sorry about the confusion with the $1061 mortgage vs. the £1950 rent (they are both monthly amounts. I meant to write £450
pw-per week, but messed up the nomanclature.
Ah, £0 for maintenance. Sure am looking forward to saying "that's not my job, mon" when something breaks around the flat. I imagine there'll be the odd light bulb and such, but DH is handy and I simply refuse to give up my God-given rights as a tenant and pay for repairs as I do while a homeowner. (I say that tongue-in-cheek, but I'm not half kidding.)
Transportation. It's all public, baby!!! Alllll public!!!! Oyster Card(s) and discount passes. The occassional hire car, but that's it. We did it before; we'll do it again. Besides, I have truly come to H-A-T-E driving. And it's nothing to do with traffic or petrol prices. Could never have imagined I'd be saying that back when I was 16. But, now? If I've forgotten milk at the market, DH is having cornflakes and water in the morning. He feels the same. (There is a small possibility DH will have a company car; but the more we think about it, the more we think we'd rather have the car allowance if it comes up.)
Health insurance. Private in US we pay that sad $418. On UK, we're quoted at £90, which includes a life insurance policy for us both. This also includes UK's Healthcash Plus which will reimburse us for co-pays, deductibles, dental, medical and optical sundries (except the really fancy glass frames and such). Hence, out the window went the co-pays and deductibles.
Lastly, I think I edited since you posted, so the savings is GBP Total £2,920 divided by USD $4,543 = 0.64274, which is a 0.35725 savings, rounded to 36%.
Yes, that's digit-for-digit (as was the first argument above). However, we will earn salaries in GBP, not USD. And, even assuming we'll be hit with the forlorn reduction in salary, and earn, let's say 20% less than we do in the US, (fortunately, recruiters are consistently telling us only I will take that hit and my salary is much lower than DH's anyway), we still come out even-steven in London. And with a better quality of life to boot (Culture, arts & entertainment, proximity to continental Europe, coastlines, watersports and wintersports are extremely important to us at this stage in our marriage, careers and lives). It's the bloody taxes, transportation and insurance that eat us alive here.
In round figures, say $100,000 combined US salaries becomes £80,000. That's ok, because my UK expenses paid from my lower UK salary compensates for that. Even better, the last niggling debt that we have to pay off in the US will evaporate faster thanks to the favourable strength of the £. (Weaker today than 2 months ago, but still!)
$100,000 - (4543 X 12) = $45,434
£80,000 - (2920 X 12) = £44,960