No hardware modifications are needed, so USB stick can still work as DVB-T or consumer band radio receiver.
Other popular homemade SDR solution is to use sound card as a A/D converter. Receiver kit for the 40 m (7 MHz) band can be bought for $15 from http://www.amqrp.org.
Overview of SDR applications for Linux (usbsoftrock, quisk DttSP + sdr-shell included): http://kb8ojh.net/sdr/linuxsdr.html.
For Windows users: SDR# (SDR-Sharp) versions 244+ (dev) have added support for RTL based SDRs supported by ExtIO.
Check also page dedicated to RTL-SDR: http://www.rtlsdr.com/.