I have done bank transfers from Lloyds TSB for £6 using their "economy" method, it was supposed to take 5 days but actually took just 3. All the other decent ones I have tried (eg. energyflow.com) have disappeared now.

If you end up sending payments fairly regularly then you can open a dollar account in the IoM with Nationwide International. You can easily send funds to it by BACS although sending payments out usually need a fax or letter written. They can write dollar cheques for $15 and wire transfers are a flat $25 (I think).

Gareth