Things I Learned in Jakarta, Indonesia: Use GPS on Your Smartphone to Get Around.

Image of Selamat Datang Monument, Jakarta, Indonesia © Mike Aquino, licensed to About.com.

In Jakarta, Indonesia, I used my trusty Nokia E72 smartphone (compare prices) with Google Maps installed. Thanks to Google Maps, I was in the unique situation of being a total Jakarta n00b, while giving directions to my taxi driver like a pro. The taxi driver didn't know where my destination was; luckily I'd saved the location as a layer in Google Maps, allowing me to show the driver exactly where I wanted him to go, and checking up on our location to make sure we were getting closer (not further) to the place I wanted to visit.

But first you gotta have a smartphone, and second, you gotta have a local prepaid SIM loaded up with credits. I had a Telkomsel SIMpati prepaid SIM (Google Translate of site) costing IDR 20,000 (about $2.50), each of which comes with IDR 5,000 (about $0.60) in credits. I got a SIM card as well as an additional IDR 50,000 (about $6) in additional call credits.

Now here's how I wasted good money: apparently with Telkomsel SIMpati, buying Internet credits is another step entirely. Because I didn't buy Internet credits (or in Indonesian prepaid phone lingo, "flash"), I ran through the IDR 55,000 in a few minutes flat, just by checking my Facebook mobile page. Big mistake.

What I should have done, immediately after I got the SIM up and running on my phone, was to follow these instructions (I first found them in this TripAdvisor page, in fact I'd printed it out, but stupidly forgot to follow through at once):

Once I'd confirmed the additional IDR 50,000 was loaded up, I should have texted "3g" (no quotes) to 3636. This lets your phone use 3G.

Next, I should have texted "flash on 10k" (no quotes) to 3636 to purchase a block of 15 MB "flash" for IDR 10,000 (about $1.20); that's how much data you'll be permitted to transmit through 3G before the "flash" credits run out. When a confirmation text comes in from 3636, reply with "flash ya" to confirm the purchase.

I ended up texting "flash on 20k" later, purchasing about 35 MB "flash" for IDR 20,000 (or about $2.50), which I wasn't able to use up in about three days of endless surfing, Google Maps use, and Foursquare checking-in.

OK, genius: how do you know how much credit you've got left? With Telkomsel, you use two different numbers: one for call credits, the other for Internet (or "flash") credits.

• To check on your call credits, dial *888# and send as a service command on your GSM phone. This enables a pop-up window that shows you how much you've got left, in Indonesian rupiah. (See this page for Telkomsel's rates.) To replenish this, you have to buy cards at your nearest convenience store and top up by following the instructions. (Better to have a local friend do this for you, as the instructions are completely in Bahasa Indonesia.)
• To check on your Internet or "flash" credits, dial *889# and send as  a service command on your GSM phone. This enables a pop-up window that shows you how many MB you've got left to use. To replenish this, make sure you have enough credits to buy "flash", then text "flash on 10k" to 3636 to buy 15 MB for IDR 10,000.

For one week, 35MB is plenty. For a few days in Bali, 15MB is adequate. Your mileage may vary. This advice works with Telkomsel-branded SIMs, but other carriers will have different rules set up.