I think a Liberal radio station would be very do-able. You could operate it as a pirate station (and risk getting raided), or you could apply for a permit from the FCC (which would cost a lot of money, and might hurt your credibility with some of the more radical elements of Liberal society).
The radio station could be given its own slot in the activity menu, and the options for running it could vary depening on whether the station was legal or not. They could include:
Pirate Station:
Liberal Ranting - The completely uncensered verbal bashing of the conservative machine! Fuck the corporations! Screw the fatcats and the oppressers! Come on, brothers and sisters, it's time to take to the streets and take these heartless assholes down!
This option would greatly effect the more liberal elements of society, while also converting a handful of moderates. It would greatly piss off the conservatives, however, and would likely trigger an FCC raid if free speech is anything less than L+.
Liberal Reasoning - Calm, rational disccusion on why liberal ideas are better than their conservative counter-parts. All humans are equal, why doesn't the government treat us as such? Millions of people are living in poverty, is it right that this should continue while corporate CEOs are allowed to make multi-million dollar saleries?
This option would work fairly well on the moderates in society, but may disenfranchise a few of the more hard-core liberals. You're not deliberately pouring gasoline on the conservative fires, however, so the FCC would be unlikey to raid unless free speech is C or C+.
Original Music - The LCS is giving local musicians a place to showcase their talents, while allowing your liberal disc-jockeys to make a few good points about the current state of society in between songs.
This option would greatly influence musicians, turning most of them liberal (The LCS is getting their music out to the masses, after all, greatly assisting their musical careers), while also influencing a good number of collage students, hippies, and visual artists such as painters and the like (You gave the musical artists a major break, maybe someone'll give them a major break as well) No copyright laws are being violated, so the FCC probably won't raid unless Free Speech is C/C+.
Popular Music - The LCS is playing the most popular songs around, causing them to be heard on thousands of radios across the city! The record companies don't like having their copyrights violated, however, and they're more than willing to complain to the "authorities" until your unlicensed transmitter is shut down.
This option could affect many people, greatly raising the popularity of the LCS. Teenagers, high school dropouts, fast food workers, and other young people would be among the most affected, causing their conservative numbers to shrink dramatically. Hard-core liberals, however, would become jaded by your musical pandering, and their numbers could shrink as well. The FCC would also be extremely likely to raid you (possibly within days) unless Free Speech was anything less than L+. If you were arrested in one of these raids, you would also have to defend yourself against a lengthy "copyright violation" charge.
Licensed Station:
Recieving a broadcasting license would require a high start-up fee ($5000?), as well as monthly fees after that ($500?). Licensed stations would have greater affects on moderate and conservative listeners (You've chosen to play by the rules!), but would have less affect on liberals (You've bowed down before the CorpGov machine, and have chosen to play by their rules!). Getting licensed would provide similar options as above, with slight modifications.
Liberal Ranting - The verbal bashing of the conservative machine, slightly censered for language and some content! Darn the corporations! Don't trust the fatcat oppressers! Listen up, brothers and sisters, it's time to circulate some petitions, maybe organize a protest. Anything to show the conservatives that we disapprove!
This effects of this option would be the same as ranting on a pirate station, except that the slight censoring would result in less liberals, and more moderates being affected. Under C+ Free Speech laws, this option could result in the FCC revoking your broadcasting license, while C Free Speech laws could result in high fines being levied against the station for offending conservative sensibilities.
Liberal Reasoning - (see above, same as pirate liberal reasoning)
Same effects as pirate liberal reasoning, execpt that fines could be levied against the station under C+ Free Speech laws for offending conservative sensibilities.
Original Music - (same as pirate original music, see above)
More or less the same effects as pirate original music, pehaps greater effects among collage students, moderates?
Popular Music - The LCS is playing the most popular songs around, causing them to be heard on thousands of radios across the city! Because of this, the liberal points brought up by your deejays during breaks are also heard be thousands of people!
This option would likely reach the most people, but would cost a good deal of money (The rights to play those songs aren't free). This option would affect the same people as pirated popular music, but to a far greater degree. This would also be reflected in the number of serious liberals who would become disenfranchised by your pandering to the record companies, the FCC, and the like.