another nice alternative is the haupaugge pvr150... you can get the oem card from amazon for about $65 although sometimes cc has the retail version (comes with remote) for $60 after mail in rebates. as for software windows media center is very nice to use, but at over $100 is expensive and does require you to reinstall your os. another popular program is myth tv. it requires a little bit of effort to get acquainted to it, but it's quite nice once you learn the ropes (and it's free).
and to answer your other ?s... yes you just hook the coax directly to the card, install some software and you're watching/recording tv on your computer monitor. also, these cards typically don't have an svideo in, but rather a composite/rca jack so you can hook up a video camera/game console/etc and watch that on your monitor as well