They are a number of ways to adapt a microphone with an XLR output connector to the USB port on a computer. Since the AT899 can provide its own power via a single AA battery installed in the provided inline AT8537 Power Module, you could simply add an XLR to USB adapter cable between the power module and the computer. This would be the least expensive way and should be fine if you are simply recording the microphone audio but do not need to monitor mic audio as it is being recorded.
If you do want to monitor the audio, you may want to consider an XLR to USB Adapter that includes a headphone jack on it so you can plug a pair of headphones into the adapter. The headphone jack on an adapter should be in circuit BEFORE the Analog to Digital converter in the adapter, and therefor provide "direct" monitoring of the microphone signal without latency. By contrast, if you monitor the audio through headphones plugged into the headphone jack on the computer, you will encounter latency as a result of the signal having to pass through the Analog to Digital converter in the adapter, through the recording program, and the Digital to Analog converter in the computer.
You could also use a USB Audio Interface or Audio Mixer with a USB output connector on it between the power module and the computer. These devices typically have headphones jacks for direct monitoring on them as well.
6 days ago