As far as card acquisition goes, I'm holding off until the new Kamigawa block releases. It's looking to be really cool. The Prerelease is on September 18th and 19th, and those events are always fun. Over here it costs $25 to enter the tournament, which gets you approximately $20 in cards, with the opportunity to win more and a fun tournament to boot. I'll be trying to scrape together information for a Prerelease tactics article again.
That's the plan I'd follow if I wanted some of the new cards and was feeling confident in my (likely rusty) playing skills. If you feel you need a brush-up, you could try to arrange a TWG game on mtgplay.com or check out the local card shops. Detailed rules questions are answered in bulk on
www.magicthegathering.com each Saturday.
If you have a fetish for artifacts, I definitely wouldn't wait to start picking up new cards. The recent Mirrodin block was stuffed full of them, and some of the artifacts they released are ridiculously good. I personally didn't like Mirrodin's metal-plane-largely-artifacts flavor and so I'm excited for Kamigawa, which it seems will have some fairly decent support for legendary creatures, lands, ect.
If you just generally want to get into Magic, the suggestion of getting a precon deck is pretty decent. I don't like them much myself, but it will get you a deck right away. Commons boxes available at most card shops is a good way to fill out the fledgling deck.
Fellfrosch is to blame for getting me started in Magic again. He gave me three boosters for a Christmas present one year, and after that I built up my collection by purchasing a fairly good number (4-5) Invasion tournament decks over time. Tournament decks only come out with the base sets, so your options are a bit limited, but they come with a full range of basic lands and a randomized selection of cards, with enough cards to equal three boosters aside from the basic lands included. Personally I favor this method for starting a card collection. You don't start out with a deck someone else built for you, but I'm not much into that anyway.