Reports from the economic development community suggest that the practice is common across many African nations (Chipchase & Tulusan, 2007; McKemey et al., 2003; Oestmann, 2003; Samuel, Shah, & Hadingham, 2005) and is not limited to teens. Slater and Kwami (2005) describe flashing as both an economic and symbolic practice, noting how "Michael, a man who flashes the same five people every morning, is not merely keeping in touch but also discharging obligations and responsibilities" (p. 10). Sey (2007) describes flashing in Ghana as one of a set of cost-saving strategies developed by users. Others note that beeping conventions in Africa differ between men and women (Alhassan, 2004; Chango, 2005).
The Uganda Search Swicki works to "harness the knowledge, passion and behavior of online communities to improve the search experience." A search for coffee + internet turns up exactly what I was hoping for: links to information about internet cafes in Kampala that serve lattes. You can also see a tag-cloud-inspired representation of what other people are searching for.
The Daily Monitor's Discover Uganda site is a one-stop portal for CHOGM visitors, but its pages on art galleries, internet access, national parks and Uganda's major towns are a great resource for other travelers.