TDWaterhouse have a very good service with access to UK and European markets. Fees are quite reasonable and their support is generally quite good (as opposed to E*Trade which are just plain arrogant). Also, you can chose to settle in US Dollars instead of Pound Sterling --which will keep the conversion fees low.
Investools? Have you seen the ads that run all over the US? I went for a
job interview in Texas a few weeks back and was surprised to see the Investools ads all over TV (in case you wonder, yes, they are quite corny). It's not worth the money. These seminars all follow the same patterns and ludicrous claims. See previous posts about Investools.
If you want a good education in that field, then you should consider
this course. That's money well spent and of an indisputable pedigree.