Karma-generation rules are in Runner's Companion, although there's an errata that is only in german at the moment that is important. The errata'd parts are: race costs karma=bp, and attributes cost new value x5 (not new value x3).
The reason to use karma-generation is that it makes getting lower-rating skills and attributes cheaper and thus using a smaller number of karma points will encourage people to make characters with smaller dicepools, rather than hyperspecialists.
You still want caps because for certain characters, jamming everything into one attribute or whatever is still the way to roll. I would suggest:
capping availability at 8 (14 with the "Restricted Gear" quality)
capping attributes to one at (max-1), and the rest lower than that (so a human could have one 5, and the rest 4 or lower)
capping skills to one at 5, rest at 3 or below, or two at 4, rest at 3 or below.
Hardcap of 4 on Magic and Resonance.
No more than 150,000Y of gear.
550 karma, but (INTxLOGx3) free bp that can only be spent on Knowledge skills.
However, if you are new to GMing/shadowrun, I would actually recommend against messing with the system at first. SR is a very finickety system (and not very well-balanced to start with) and poking around with it is tricky and liable to make things worse. I'd really recommend running a more standard 400 bp game until you feel like your really understand the system and how it works.
And now All4BigGuns will explain why he hates karma-generation to provide an alternate perspective: