Melissa_Ward - 5:19 pm on Oct 28, 2011 (gmt 0)
The easiest way is to use an app like Tab Press to create a Fangate. Set the fan page to default to your custom landing page (Edit info, Manage Permissions) and give them a reason to "like" the page. Whether it's a promotion, ie: coupon or something similar. The best way is to create your own app so you have more control and are not advertising someone else's app.
The challenge comes in keeping people there by providing useful and relevant content.