Topic pretty much sums it up.

Is there an online page that offers a general rules/mechanic summary and character creation summary.

BIG WFRP3e guy, and don't wish to make ANOTHER investment without giving it a go first. Any suggestions?

Thanks,..

You mean something like this? An adventure and some quickstart rules? Remember, random search engine is your friend.

http://www.fantasyflightgames.com/edge_news.asp?eidn=477

Dark Heresy is a completely different kettle of fish to WHFRP 3e. If you had knowledge of 2e i would say its very similar but as it stands i'd say this:

Dark Heresy is a D% system (that is your attributes range from 1 to 100 and you have to roll under them to succeed on a check). You have a range of skills that allow you to attempt physical feats, social activities or to understand something. You then have Talents which include weapon proficiencies, complex social or combat options or simply improve your character's toughness or abilitiy to use psychic powers.

The classes available in the core book (which is what i would suggest stick to for your first game) are as follows:
Arbitrator - bad ass policemen that are tough and have some social skills

Adepts - knowledge masters with a small degree of social skills

Assassins - expert killers that can focus on ranged or melee combat but do both with finesse

Cleric - pious warrior priests that worship the God Emperor

Guardsmen - not literally just Imperial guardsmen but a catch all for any military or mercenary types

Imperial Psykers - sanctioned psykers whose warp fuelled psychic powers are potent but carry great risks

Scum - covers all the villainous, larcenous and desperado types. good at getting what they want through social or combat skills

Tech-priest - members of the Adeptus Mechanics and the best at understanding and using the prosaic mixtrure of technology in the 41st millenium

Best bet is to come up with a character concept and get the group to help you pick the class that will best suit it. A bit more information can be found here http://warhammer40k.wikia.com/wiki/Dark_Heresy but it is far from up to date.

The core book is all you need as it is packed full of 40k goodness. Here is a very cool and simple character generator from just the core book and the Inquisitor's Handbook that I used to get familiar with the character creation process:

http://suptg.thisisnotatrueending.com/dhadvanced.html

Interrogator Z