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 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 Lake Malawi.