I am a British motorsports fan, and have followed FIA Formula One for many years.

The politics and Ferrari-bias of the authorities have worn thin and
I'm losing interest.  UK satellite TV carries IRL Indycars and it
appears to start today.  What should I know before I get into watching
it?  I've read a few websites today and see the driver MANNING for the
TARGET team comes from the same area of the UK as I do, so I intend
adopting him as 'my driver.

I am confused with what an Indycar and what a Champcar is.  What're
the differences, and if I'm going to get hooked on one or the other
series, which is most popular in the US?  Secondly, as a Formula One
fan, what similarities and differences should I look out for in
either?

(IRL Indycar is definitiely carries on the satellite service Sky
Digital in the UK, so if Champcar isn't, getting hooked on that when
it starts later in the year is not an option!)

The difference between the Champ Car series and the IRL go back to the
late 1990s - 1996 or 1997, IIRC.  The IRL was started by Tony George,
owner of the Indianapolis Motor Speedway, to create a more
NASCAR-style open-wheel racing league.  There are only two or three
approved chassis makers, and two approved engine suppliers for the
IRL, and the IRL only races on oval tracks.  Champ Cars is the short
name for Championship Auto Racing Teams, or CART.  CART is much closer
to Formula 1 - there is more diversity in engine and chassis
technology, and the CART races take place both on oval tracks and road
courses, as well as street courses.  The "big name" teams from the
late '90s - Team Green, Penske, et. al. were all major participants in
CART, but as CART's popularity waned, all moved to IRL.  One possible
reason for this mass migration is the Indy 500 - because the head of
the IRL also owns the Indianapolis Motor Speedway, CART lost its
marquee race when the IRL was formed.  The IRL is now the more popular
of the two series, but neither is very much watched in the USA, with
NASCAR being the racing series of choice.

Now, which open-wheel series you watch is completely up to you, and
because I don't know what aspects of open-wheel racing appeal to you
more, I'm not going to make any presumptions and say "you should watch
this series over the other". IRL, because of its tight specifications,
emphasizes driver skill and team pit stop efficiency more than team
budget and technology.  If that aspect appeals to you, then you should
watch IRL.  However, if it is the technological wizardry of each
team's cars that appeal to you, then CART is the more desirable of the
two series.  Were I you, I think I would give up on open-wheel racing
entirely and watch BTCC or WRC instead.

Hope that helps :-)
szehui-ga

A slight correction to the very useful comment above from szehui-ga.
As of the 2003 competition season, ChampCar, in an effort to reduce
costs, mandated that all teams would lease a common engine type from
Ford-Cosworth, the XFE. This one-engine regime continues for the 2004
race season. The chassis are also limited, to either one made by Lola,
or one made by Reynard. All Champ Cars must run the sponsor's tires,
Bridgestones. Basically, there is no very little difference between
the IRL and Champ Car... coupled with Champ Car's financial
difficulties over the last year, and you can see why there are rumours
that the IRL will acquire Champ Car eventually, and bring the whole
soap opera back full circle.