The SAS support website http://support.sas.com/ has a wealth of information and DOC for what you're asking. A search at the site using your keywords generates several hits. Also, a Google advanced search using the keywords below also provides many hits:
+missover +truncover site:sas.com
Also, you can add the following PUTLOG (new with SAS 9) statement to generate additional diagnostics with your DATA step to see how SAS handles the various conditions.
As Scott suggested, the doc on column pointer control may prove useful. In addition, it helps to see the data in a "fixed pitch font", where the letter 'i' takes up the same amount of physical space on the line as the letter 'w':
0 0 1 1 2 2 3
1201 2008-10-31 5702345678 2334
In the above example, I've taken your data and made it appear in a fixed font. I've added some "column info" above your data. So, you can see that position 1 (or @1) in the input line holds the value '1'. The date 2008-10-31 starts in position 6 (or @6) -- it may only be the 4th variable you read, but it starts in position 6 on the input line (each . represents a column position -- I've only shown the starting 1 and 5 in the column info).
Similarly, your value '570' starts in position 19 or @19 and your value '2334' starts in position 30 or @30.... so working with this "fixed pitch" view of your data, may help you figure out the correct INPUT statement. In order to use column pointer control effectively, ALL your data lines must line up the same way, in the same columns, when you look at them in NOTEPAD. (I made a couple of extra dummy datalines, so you could see everything "line up".)