CorDarei and PaulTB have already provided some really good info, but... I just couldn't ignore a question from someone who considers me "infamous." (I'm not sure how to feel about that, but I suppose it's better than no fame at all
)
Just to add to what's already been explained, first of all here's a link to one post from the sci.lang.japan thread that CorDarei mentioned, which sums up some examples of the contrasting usage between 「探す」 and 「捜す」.
Moving on to your other questions:
cacawate said:
Thanks for the responses. To clear things up can I use each for intangible things? As in 失恋を捜すand 恋を探す? Thanks again.
「恋を探す」
is fine. 「失恋を探す」 (with either kanji) sounds strange to me because of the meaning of 失恋. You realize that this doesn't mean "lost love" as in an 'old flame' (or someone you had feelings for but lost touch with, or the like), but rather it means rejected/unrequited love. 「失恋を探してる」 would make it sound like the person in question is actively seeking to get rejected by the object of their affection.
Finally, regarding 「探る」, let me give a rough, abridged translation with example sentences from 大辞泉:
1) To use the tactile senses of e.g. one's hands and feet to seek/feel out something that cannot be seen.
「小銭がないかとポケットを探る」「暗闇を探る」 (note here that を is marking the area/"space" being searched, not what's being searched for, though a quick Google search suggests that this might be somewhat flexible.)
2) To indirectly gauge the thoughts, condition, movement, location of one's opponent/another party.
「敵情を探る」「探るような目つき」
3) To observe/investigate for purposes of clarifying something as-of-yet unknown.
「語源を探る」「事故の原因を探る」
4) To seek out the best possible way of doing something.
「解決の糸口を探る」
5) To seek out and enjoy little-known lands/areas or beautiful scenery.
「秘境を探る」「古都の秋を探る」
Anyway, I have no idea if this will be helpful or not, but for whatever it's worth, there it is.
If there are specific examples that you're still unsure of, I find that judicious use of Google is a really good way to get an idea of the extent to which native speakers actually use a particular phrase.