Hi ,, I am level 17 and have had Faendal (sp? He archer follower from Riverwood) follow me so far but he just got killed by the bandits at the camp just outside Whiterun. I made great use of him by having him carry items found.
I just got Lydia as a housecarl , ... My question is, can I have her wait back at Whiterun and use that tough girl from The Bannered Mare follow me on quests ... At least for now?

Of course. You can have one follower at a time, and you can replace them as you please.

What Shadow said. If Lydia is not following you, she will return to Breezehome so she'll still be readily available to follow you again if you decide to do so.

If you're on console, just tell Lydia that you will part ways and go get another follower. Lydia will wait in Breezehome, if you own it, otherwise Dragonsreach. Since she's your housecarl, she will follow you again for free any time you'll ask her. (If you just tell her to wait, she will still be considered your active follower, and you can't have another.)

If you're on PC, there are a few mods that will allow you to have multiple followers following you at once. The most popular are probably http://skyrim.nexusmods.com/mods/15524//?and http://skyrim.nexusmods.com/mods/14037//?.

http://uesp.net/wiki/Skyrim:Followers

Skyrim is full of followers who can adventure with you and "carry your burdens". If you dismiss one follower, they'll just go back to where you originally found them, and you can recruit another.

Awesome. Thank u for all the quick replies everyone. Very helpful.

I believe you can have one human & one animal follower with you at any time.

If you love followers, and are into mods, there is one called UFO (Ultimate Follower Overhaul) that allows you to have several at once, your own little army, lol. But you need to know what your doing when installing them, Gopher's channel on Youtube is a good place to start.