Douglas Sweeney and Mark Rogers have a nice article about how 'altar calls' got their start in evangelical churches. It's called Walk the Aisle, and is in this months Christianhistory.net. Contrary to what many people believe, altar calls are not really a biblical concept. It was popularized during the 1800's. You can read the article for the whole scoop.
We had an altar call at the end of every single service in the church I came to faith in. I can remember many a Sunday when I would sit there in the pew and wrestle with myself whether or not I should "go forward." I finally did walk the aisle probably sometime in late 1988. Though I had already made a conscious decision to surrender my life to Jesus before that. I did that twenty years ago this week. I can remember it like it was yesterday - standing in a hospital parking lot, leaning up against our '73 Torino, and I finally admitted that I needed help with this thing called life; I couldn't do it on my own anymore; so I told God that I needed him and I asked Jesus to come into my heart and lead me and guide me in what I should do. Then, probably a few Sundays after that, I walked the aisle and made it "official" in church (you know, so they could count it in the church record books).
When I first became a pastor I used altar calls quite a bit, or I would have everyone bow their head, close their eyes, and raise their hand; Or I would have them fill out a card. Something. But I don't do it anymore. I have come to see conversion as much more of a process. And it was for me. I 'put the stake in the ground' so-to-speak in the hospital parking lot - that's when I made a conscious decision to give my life to Christ - but my heart had been undergoing change long before that. And it wasn't until a year or so after that - when I was discipled in a small group - that I really understood much of what had happened.
Sometimes I wonder if altar calls don't still have a place though. You know, it kind of forces us to make a conscious decision. I don't know that that "settles" anything, but maybe it can help. I don't know. Just thinking...