The RTL2832 USB dongle recievers are already common knowledge among many radio amateurs and a way to introduce the SDR technology to everyone - although i'm not fond of it, given it's poor performance. We are basically talking about a TV-tuner using custom software that allows it to work just as a ham radio reciever, with the obvious limitations of a US$ 10 product no bigger than my thumb. Because they are cheap and they offer a wide frequency coverage though, they got really popular and manufacturers even started making them especially for amateurs.
Next need though would be transmit capabilities; enter the Hides UT-100, an USB dongle with transmit and recieve, the same wideband coverage, but with a heftier price - around US$ 200-230.
Based on a IT9507 ccHDtv all-in-one transmitter chip, an IT9133 RF tuner + demodulator and an AD8345 mixer, this little wonder works from 50Mhz to 950Mhz plus 1200Mhz to 1350Mhz in various configurations: the UT-100A can transmit 2Mhz to 8Mhz wide and recieve 5Mhz to 8Mhz wide, the B (the one you want) has the narrower 2Mhz to 4Mhz recieve, the C only transmits and the D only recieves. There are separate antenna ports for RX and TX, the output power is 0dBm (1mW) and there is a digital attenuator from +6dB to -25dB to deal with strong signals on recieve.
The software of the UT-100 allows transmission of video streams from webcams or prerecorded materials - there are already good results is the ATV community, look at OE7DBH's experiments, and hopefully someone will make the effort to adapt a decent software to use SSB and FM on these.
For more info on these, please review the datasheet.