im just starting out learning to play with chords, i had no need to before, but now im playing with a band at church, and i was just wondering if you had any tips.
actually, i was wondering what the best way to practise by myself is for this, because all the songs are self written by the youth pastor, and i dont have access to a recording.

Do you mean chords on your bass, or playing along to a chord the guitarist/pianist is using?

playin along with the guitar and such

try playing along with cds/records, and learing songs by ear, eventually you'll develop, relative or perfect pitch.

have them give you what is known as a chord chart. it tells what kind of chords, the key, and for how long to play them. use the chords arpeggios. for example. a c major 7 chord you could use C E G B. those are called chord tones. Typically you should use chord tones because well they define the chord. but dont limit yourself to strictly arpeggios.
im sure there are some great threads around here about arpeggio usage. search em dude.

actually, i was wondering what the best way to practise by myself is for this, because all the songs are self written by the youth pastor, and i dont have access to a recording.
I'm not sure how your circumstances compare to mine, but this is what I do: our sound guys are always present during practice sessions (it's their only opportunity to sort out lurking sound issues before the next church service and to prepare the lyrics for our overhead projector). They record the whole practice session for me and copy it to a flash drive at the end of the session. At home I seperate all songs using Audacity and practice with problem-songs using the chord progressions written above the lyrics. If needed I draw one or more scale diagrams somewhere on the page and/or make notes next to some of the phrases, as reminders (to what works best or better / alternative patterns) during play.

By the time I play it in church, I've done everything possible to help myself and I know exactly what I'd like to do for each song.

This stuff makes good material for future practice sessions.

yeah I agree with pinkflamingo....chord chart then play outline the chords with chord tones. if they are lazy at least get the roots from them and just play 1 - 5- 8.....is what I use a lot in a improv musician jam where sometimes you got to feel the roots out cause the other musicians don't bother telling the chord progression. find the roots and go from there.

If you aren't comfortable with improvising over chords yet, I'd follow what bahamabass says. stick to roots and fifths and octaves, focus on the rhythm, and listen.

ive been playin with the group quite a bit lately, and im doin pretty good. there are a few songs where the changes are a little bit weird sometimes, but for the most part im learning and doing very well. ive began with the arpegios in some of the slower songs where tehre is only one or 2 chords every line in the song or so. and that really fills out the song better than just the roots. thanks for everyones input.

Also try to get hold of the major scale and all its position. I also play in church and most of the time the roots of the chords in the song are made up of the major scale of the given key (our term for it is 'family chords'). That, plus the chord tones (arpeggios) would give you a lot of note choices.