Minibuses are ubiquitous, cheap, and fast. For under a dollar, you can get almost anywhere in the city. The problem, is that bus routes are not posted, and a novice is likely to get lost. Do not be afraid to ask a conductor where he's headed.
For the uninitiated, then, a taxi might be a better option, at least initially. There are no meters in Zambia's taxis, so prices are somewhat negotiable. Be sure to set a price before getting in the cab. (A tip for newbies: Ask at a hotel lobby how much your trip should cost. If the cab driver states a higher price, mention that you're happy to ride a mini-bus. Watch the price drop. )
In 2000, Lusaka got its first official mall, and the reception was huge. The South African equivalent of Wal-Mart -- GAME Stores -- was the anchor, and locals and ex-pats alike flocked to it. The mall also features some high-end boutiques, a bookshop, a Subway restaurant (but without turkey!?), some memorabilia shops, and some clothing stores.
For a more "African" feel, though, you need to go Kabwata Cultural Village on Burma Road. There you will find dozens of curio-makers and salesmen. You will quickly learn that "looking is free," but the goods are not. Be prepared to spend a while, and don't be afraid to dicker.
Lusaka boasts many Western-styled bars (e.g., Brown's and McGinty's, mainly used by tourists, and ex-pats). However, Zambians love to drink; there are, therefore, a number of bars frequented by locals, as well. However, these change often.
Accommodation in Lusaka runs the gamut.
There are a number of mid-range accommodation options, as well.
Of course, there are game parks (like South Luangwa National Park) scattered throughout Zambia, and many Lusakans visit them on the weekends. Heading to Livingstone for a few days is also a popular choice. Finally, some people like the laid-back feel of Malawi's Cape Maclear.