What a super-site! Raising my son Swedish-English bilingual with very little time for research into how to actually go about it in the best way, I'm just thrilled to have found this site. Since our son's birth seven years ago, we have lived in a small US university-town without easy access other Swedish speakers. Thus, I have been the only person to interact in Swedish with my son on a daily basis (my husband is American). The first year, things were fairly easy with me being the main care taker and only about 10-15 hours/week of English daycare. My son's first word at around one year of age was in Swedish ("kaka" meaning cookie -- and yes, he still loves sweets) and he clearly understood both English and Swedish at that age.
However, once he began full-time daycare, English became the stronger language. I managed to maintain Swedish at home, that is, me speaking Swedish and my son mostly answering in English, up until Kindergarten when things changed drastically; as a consequence of his school and activity schedule, there was very little time for us to speak Swedish. 8:15 - 3:00PM he spent at school interacting only in English, 3-5PM he either had play dates or was involved in after-school activities which naturally were all in English, and in the late afternoons and evenings as well as on weekends it became awkward for my son and I to interact in Swedish since it would mean excluding my husband (who speaks no Swedish) from conversation. Our main interaction in Swedish took place in the early mornings on weekdays before school started. This together with tons of Swedish movies and TV-shows (our region-free DVD player got a lot of use), seemed to enable my son to keep Swedish alive at some level.
To help him become more fluent, we spent 5 months in Sweden where my son attended public school (my son missed fall of American 1st grade). In Sweden, he was very quiet at school the first two weeks, clearly observing and listening intently. After that he spoke just as much as all the other kids, although lacking vocabulary as well as grammar, sometimes to the point where other kids did not understand him. By week 6, he seemed to turn a corner and became almost native-like very quickly.
It'll be interesting to see what happens to his Swedish now that we are back in the US to the same language/school schedule as in Kindergarten. I'm sure I'll be checking in with this site often for advice as well as consult a fantastic little book I just discovered - The Bilingual Edge by King and Mackey (fast and easy to read, excellent practical advice, and it only cost about $10!) Luckily, my son made several friends in Sweden during his school attendance there and is keeping in touch with them through emails and phone calls in Swedish (the beauty of Swedish 7-10 year-olds is that they don't speak English). Obviously, occasional contact with Swedish friends will not be enough to maintain his Swedish and neither will our 2-3 week visits to Sweden once a year. I'm going to have to get creative and need all the help I can get.