"Can I get this if I use a condom?"
Yes.

"How soon after getting infected will I show signs of this?"
The eggs (nits) hatch in 5-10 days. Once they hatch it takes another week for them to mature. Symptoms of itching can begin within days of infestation.

"How do I get rid of this?"
The doctor will prescribe a lotion to use and you need to have the partners treated. You may need to retreat the area 10 days after the first treatment.

"How can I tell if I am clean from pubic lice?"
Self inspection is difficult but possible with a magnifying glass and a bright light or you can ask your partner to check you and look for eggs clinging to pubic hair.

"Can I get this just from sleeping on my friend's couch?"
Yes, it is known to be transmitted through contaminated sheets and bedding.